Merge pull request #566 from JustOff/PR_libwebp-1.0.0

Update libwebp to v1.0.0 + known security patches

5 files changed, 179 insertions, 170 deletions

diff --git a/media/libwebp/webp/decode.h b/media/libwebp/webp/decode.h
index 4c5e74ac3..2165e96c9 100644
--- a/media/libwebp/webp/decode.h
+++ b/media/libwebp/webp/decode.h
@@ -36,39 +36,39 @@ typedef struct WebPDecoderConfig WebPDecoderConfig;
 
 // Return the decoder's version number, packed in hexadecimal using 8bits for
 // each of major/minor/revision. E.g: v2.5.7 is 0x020507.
-WEBP_EXTERN(int) WebPGetDecoderVersion(void);
+WEBP_EXTERN int WebPGetDecoderVersion(void);
 
 // Retrieve basic header information: width, height.
 // This function will also validate the header, returning true on success,
 // false otherwise. '*width' and '*height' are only valid on successful return.
 // Pointers 'width' and 'height' can be passed NULL if deemed irrelevant.
-WEBP_EXTERN(int) WebPGetInfo(const uint8_t* data, size_t data_size,
-                             int* width, int* height);
+WEBP_EXTERN int WebPGetInfo(const uint8_t* data, size_t data_size,
+                            int* width, int* height);
 
 // Decodes WebP images pointed to by 'data' and returns RGBA samples, along
 // with the dimensions in *width and *height. The ordering of samples in
 // memory is R, G, B, A, R, G, B, A... in scan order (endian-independent).
 // The returned pointer should be deleted calling WebPFree().
 // Returns NULL in case of error.
-WEBP_EXTERN(uint8_t*) WebPDecodeRGBA(const uint8_t* data, size_t data_size,
-                                     int* width, int* height);
+WEBP_EXTERN uint8_t* WebPDecodeRGBA(const uint8_t* data, size_t data_size,
+                                    int* width, int* height);
 
 // Same as WebPDecodeRGBA, but returning A, R, G, B, A, R, G, B... ordered data.
-WEBP_EXTERN(uint8_t*) WebPDecodeARGB(const uint8_t* data, size_t data_size,
-                                     int* width, int* height);
+WEBP_EXTERN uint8_t* WebPDecodeARGB(const uint8_t* data, size_t data_size,
+                                    int* width, int* height);
 
 // Same as WebPDecodeRGBA, but returning B, G, R, A, B, G, R, A... ordered data.
-WEBP_EXTERN(uint8_t*) WebPDecodeBGRA(const uint8_t* data, size_t data_size,
-                                     int* width, int* height);
+WEBP_EXTERN uint8_t* WebPDecodeBGRA(const uint8_t* data, size_t data_size,
+                                    int* width, int* height);
 
 // Same as WebPDecodeRGBA, but returning R, G, B, R, G, B... ordered data.
 // If the bitstream contains transparency, it is ignored.
-WEBP_EXTERN(uint8_t*) WebPDecodeRGB(const uint8_t* data, size_t data_size,
-                                    int* width, int* height);
+WEBP_EXTERN uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size,
+                                   int* width, int* height);
 
 // Same as WebPDecodeRGB, but returning B, G, R, B, G, R... ordered data.
-WEBP_EXTERN(uint8_t*) WebPDecodeBGR(const uint8_t* data, size_t data_size,
-                                    int* width, int* height);
+WEBP_EXTERN uint8_t* WebPDecodeBGR(const uint8_t* data, size_t data_size,
+                                   int* width, int* height);
 
 
 // Decode WebP images pointed to by 'data' to Y'UV format(*). The pointer
@@ -80,13 +80,13 @@ WEBP_EXTERN(uint8_t*) WebPDecodeBGR(const uint8_t* data, size_t data_size,
 // have a common stride returned as '*uv_stride'.
 // Return NULL in case of error.
 // (*) Also named Y'CbCr. See: http://en.wikipedia.org/wiki/YCbCr
-WEBP_EXTERN(uint8_t*) WebPDecodeYUV(const uint8_t* data, size_t data_size,
-                                    int* width, int* height,
-                                    uint8_t** u, uint8_t** v,
-                                    int* stride, int* uv_stride);
+WEBP_EXTERN uint8_t* WebPDecodeYUV(const uint8_t* data, size_t data_size,
+                                   int* width, int* height,
+                                   uint8_t** u, uint8_t** v,
+                                   int* stride, int* uv_stride);
 
 // Releases memory returned by the WebPDecode*() functions above.
-WEBP_EXTERN(void) WebPFree(void* ptr);
+WEBP_EXTERN void WebPFree(void* ptr);
 
 // These five functions are variants of the above ones, that decode the image
 // directly into a pre-allocated buffer 'output_buffer'. The maximum storage
@@ -96,22 +96,22 @@ WEBP_EXTERN(void) WebPFree(void* ptr);
 // The parameter 'output_stride' specifies the distance (in bytes)
 // between scanlines. Hence, output_buffer_size is expected to be at least
 // output_stride x picture-height.
-WEBP_EXTERN(uint8_t*) WebPDecodeRGBAInto(
+WEBP_EXTERN uint8_t* WebPDecodeRGBAInto(
     const uint8_t* data, size_t data_size,
     uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
-WEBP_EXTERN(uint8_t*) WebPDecodeARGBInto(
+WEBP_EXTERN uint8_t* WebPDecodeARGBInto(
     const uint8_t* data, size_t data_size,
     uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
-WEBP_EXTERN(uint8_t*) WebPDecodeBGRAInto(
+WEBP_EXTERN uint8_t* WebPDecodeBGRAInto(
     const uint8_t* data, size_t data_size,
     uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
 
 // RGB and BGR variants. Here too the transparency information, if present,
 // will be dropped and ignored.
-WEBP_EXTERN(uint8_t*) WebPDecodeRGBInto(
+WEBP_EXTERN uint8_t* WebPDecodeRGBInto(
     const uint8_t* data, size_t data_size,
     uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
-WEBP_EXTERN(uint8_t*) WebPDecodeBGRInto(
+WEBP_EXTERN uint8_t* WebPDecodeBGRInto(
     const uint8_t* data, size_t data_size,
     uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
 
@@ -122,7 +122,7 @@ WEBP_EXTERN(uint8_t*) WebPDecodeBGRInto(
 // 'u_size' and 'v_size' respectively.
 // Pointer to the luma plane ('*luma') is returned or NULL if an error occurred
 // during decoding (or because some buffers were found to be too small).
-WEBP_EXTERN(uint8_t*) WebPDecodeYUVInto(
+WEBP_EXTERN uint8_t* WebPDecodeYUVInto(
     const uint8_t* data, size_t data_size,
     uint8_t* luma, size_t luma_size, int luma_stride,
     uint8_t* u, size_t u_size, int u_stride,
@@ -213,7 +213,7 @@ struct WebPDecBuffer {
 };
 
 // Internal, version-checked, entry point
-WEBP_EXTERN(int) WebPInitDecBufferInternal(WebPDecBuffer*, int);
+WEBP_EXTERN int WebPInitDecBufferInternal(WebPDecBuffer*, int);
 
 // Initialize the structure as empty. Must be called before any other use.
 // Returns false in case of version mismatch
@@ -223,7 +223,7 @@ static WEBP_INLINE int WebPInitDecBuffer(WebPDecBuffer* buffer) {
 
 // Free any memory associated with the buffer. Must always be called last.
 // Note: doesn't free the 'buffer' structure itself.
-WEBP_EXTERN(void) WebPFreeDecBuffer(WebPDecBuffer* buffer);
+WEBP_EXTERN void WebPFreeDecBuffer(WebPDecBuffer* buffer);
 
 //------------------------------------------------------------------------------
 // Enumeration of the status codes
@@ -277,7 +277,7 @@ typedef enum VP8StatusCode {
 // within valid bounds.
 // All other fields of WebPDecBuffer MUST remain constant between calls.
 // Returns NULL if the allocation failed.
-WEBP_EXTERN(WebPIDecoder*) WebPINewDecoder(WebPDecBuffer* output_buffer);
+WEBP_EXTERN WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer);
 
 // This function allocates and initializes an incremental-decoder object, which
 // will output the RGB/A samples specified by 'csp' into a preallocated
@@ -289,7 +289,7 @@ WEBP_EXTERN(WebPIDecoder*) WebPINewDecoder(WebPDecBuffer* output_buffer);
 // colorspace 'csp' is taken into account for allocating this buffer. All other
 // parameters are ignored.
 // Returns NULL if the allocation failed, or if some parameters are invalid.
-WEBP_EXTERN(WebPIDecoder*) WebPINewRGB(
+WEBP_EXTERN WebPIDecoder* WebPINewRGB(
     WEBP_CSP_MODE csp,
     uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
 
@@ -304,7 +304,7 @@ WEBP_EXTERN(WebPIDecoder*) WebPINewRGB(
 // In this case, the output buffer will be automatically allocated (using
 // MODE_YUVA) when decoding starts. All parameters are then ignored.
 // Returns NULL if the allocation failed or if a parameter is invalid.
-WEBP_EXTERN(WebPIDecoder*) WebPINewYUVA(
+WEBP_EXTERN WebPIDecoder* WebPINewYUVA(
     uint8_t* luma, size_t luma_size, int luma_stride,
     uint8_t* u, size_t u_size, int u_stride,
     uint8_t* v, size_t v_size, int v_stride,
@@ -312,19 +312,19 @@ WEBP_EXTERN(WebPIDecoder*) WebPINewYUVA(
 
 // Deprecated version of the above, without the alpha plane.
 // Kept for backward compatibility.
-WEBP_EXTERN(WebPIDecoder*) WebPINewYUV(
+WEBP_EXTERN WebPIDecoder* WebPINewYUV(
     uint8_t* luma, size_t luma_size, int luma_stride,
     uint8_t* u, size_t u_size, int u_stride,
     uint8_t* v, size_t v_size, int v_stride);
 
 // Deletes the WebPIDecoder object and associated memory. Must always be called
 // if WebPINewDecoder, WebPINewRGB or WebPINewYUV succeeded.
-WEBP_EXTERN(void) WebPIDelete(WebPIDecoder* idec);
+WEBP_EXTERN void WebPIDelete(WebPIDecoder* idec);
 
 // Copies and decodes the next available data. Returns VP8_STATUS_OK when
 // the image is successfully decoded. Returns VP8_STATUS_SUSPENDED when more
 // data is expected. Returns error in other cases.
-WEBP_EXTERN(VP8StatusCode) WebPIAppend(
+WEBP_EXTERN VP8StatusCode WebPIAppend(
     WebPIDecoder* idec, const uint8_t* data, size_t data_size);
 
 // A variant of the above function to be used when data buffer contains
@@ -332,7 +332,7 @@ WEBP_EXTERN(VP8StatusCode) WebPIAppend(
 // to the internal memory.
 // Note that the value of the 'data' pointer can change between calls to
 // WebPIUpdate, for instance when the data buffer is resized to fit larger data.
-WEBP_EXTERN(VP8StatusCode) WebPIUpdate(
+WEBP_EXTERN VP8StatusCode WebPIUpdate(
     WebPIDecoder* idec, const uint8_t* data, size_t data_size);
 
 // Returns the RGB/A image decoded so far. Returns NULL if output params
@@ -340,15 +340,16 @@ WEBP_EXTERN(VP8StatusCode) WebPIUpdate(
 // specified during call to WebPINewDecoder() or WebPINewRGB().
 // *last_y is the index of last decoded row in raster scan order. Some pointers
 // (*last_y, *width etc.) can be NULL if corresponding information is not
-// needed.
-WEBP_EXTERN(uint8_t*) WebPIDecGetRGB(
+// needed. The values in these pointers are only valid on successful (non-NULL)
+// return.
+WEBP_EXTERN uint8_t* WebPIDecGetRGB(
     const WebPIDecoder* idec, int* last_y,
     int* width, int* height, int* stride);
 
 // Same as above function to get a YUVA image. Returns pointer to the luma
 // plane or NULL in case of error. If there is no alpha information
 // the alpha pointer '*a' will be returned NULL.
-WEBP_EXTERN(uint8_t*) WebPIDecGetYUVA(
+WEBP_EXTERN uint8_t* WebPIDecGetYUVA(
     const WebPIDecoder* idec, int* last_y,
     uint8_t** u, uint8_t** v, uint8_t** a,
     int* width, int* height, int* stride, int* uv_stride, int* a_stride);
@@ -368,7 +369,7 @@ static WEBP_INLINE uint8_t* WebPIDecGetYUV(
 // Returns NULL in case the incremental decoder object is in an invalid state.
 // Otherwise returns the pointer to the internal representation. This structure
 // is read-only, tied to WebPIDecoder's lifespan and should not be modified.
-WEBP_EXTERN(const WebPDecBuffer*) WebPIDecodedArea(
+WEBP_EXTERN const WebPDecBuffer* WebPIDecodedArea(
     const WebPIDecoder* idec, int* left, int* top, int* width, int* height);
 
 //------------------------------------------------------------------------------
@@ -416,7 +417,7 @@ struct WebPBitstreamFeatures {
 };
 
 // Internal, version-checked, entry point
-WEBP_EXTERN(VP8StatusCode) WebPGetFeaturesInternal(
+WEBP_EXTERN VP8StatusCode WebPGetFeaturesInternal(
     const uint8_t*, size_t, WebPBitstreamFeatures*, int);
 
 // Retrieve features from the bitstream. The *features structure is filled
@@ -457,7 +458,7 @@ struct WebPDecoderConfig {
 };
 
 // Internal, version-checked, entry point
-WEBP_EXTERN(int) WebPInitDecoderConfigInternal(WebPDecoderConfig*, int);
+WEBP_EXTERN int WebPInitDecoderConfigInternal(WebPDecoderConfig*, int);
 
 // Initialize the configuration as empty. This function must always be
 // called first, unless WebPGetFeatures() is to be called.
@@ -477,14 +478,14 @@ static WEBP_INLINE int WebPInitDecoderConfig(WebPDecoderConfig* config) {
 // The return WebPIDecoder object must always be deleted calling WebPIDelete().
 // Returns NULL in case of error (and config->status will then reflect
 // the error condition, if available).
-WEBP_EXTERN(WebPIDecoder*) WebPIDecode(const uint8_t* data, size_t data_size,
-                                       WebPDecoderConfig* config);
+WEBP_EXTERN WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size,
+                                      WebPDecoderConfig* config);
 
 // Non-incremental version. This version decodes the full data at once, taking
 // 'config' into account. Returns decoding status (which should be VP8_STATUS_OK
 // if the decoding was successful). Note that 'config' cannot be NULL.
-WEBP_EXTERN(VP8StatusCode) WebPDecode(const uint8_t* data, size_t data_size,
-                                      WebPDecoderConfig* config);
+WEBP_EXTERN VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size,
+                                     WebPDecoderConfig* config);
 
 #ifdef __cplusplus
 }    // extern "C"
diff --git a/media/libwebp/webp/demux.h b/media/libwebp/webp/demux.h
index 454f6914b..555d64133 100644
--- a/media/libwebp/webp/demux.h
+++ b/media/libwebp/webp/demux.h
@@ -71,7 +71,7 @@ typedef struct WebPAnimDecoderOptions WebPAnimDecoderOptions;
 
 // Returns the version number of the demux library, packed in hexadecimal using
 // 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507.
-WEBP_EXTERN(int) WebPGetDemuxVersion(void);
+WEBP_EXTERN int WebPGetDemuxVersion(void);
 
 //------------------------------------------------------------------------------
 // Life of a Demux object
@@ -85,7 +85,7 @@ typedef enum WebPDemuxState {
 } WebPDemuxState;
 
 // Internal, version-checked, entry point
-WEBP_EXTERN(WebPDemuxer*) WebPDemuxInternal(
+WEBP_EXTERN WebPDemuxer* WebPDemuxInternal(
     const WebPData*, int, WebPDemuxState*, int);
 
 // Parses the full WebP file given by 'data'. For single images the WebP file
@@ -109,27 +109,32 @@ static WEBP_INLINE WebPDemuxer* WebPDemuxPartial(
 }
 
 // Frees memory associated with 'dmux'.
-WEBP_EXTERN(void) WebPDemuxDelete(WebPDemuxer* dmux);
+WEBP_EXTERN void WebPDemuxDelete(WebPDemuxer* dmux);
 
 //------------------------------------------------------------------------------
 // Data/information extraction.
 
 typedef enum WebPFormatFeature {
-  WEBP_FF_FORMAT_FLAGS,  // Extended format flags present in the 'VP8X' chunk.
+  WEBP_FF_FORMAT_FLAGS,      // bit-wise combination of WebPFeatureFlags
+                             // corresponding to the 'VP8X' chunk (if present).
   WEBP_FF_CANVAS_WIDTH,
   WEBP_FF_CANVAS_HEIGHT,
-  WEBP_FF_LOOP_COUNT,
-  WEBP_FF_BACKGROUND_COLOR,
-  WEBP_FF_FRAME_COUNT    // Number of frames present in the demux object.
-                         // In case of a partial demux, this is the number of
-                         // frames seen so far, with the last frame possibly
-                         // being partial.
+  WEBP_FF_LOOP_COUNT,        // only relevant for animated file
+  WEBP_FF_BACKGROUND_COLOR,  // idem.
+  WEBP_FF_FRAME_COUNT        // Number of frames present in the demux object.
+                             // In case of a partial demux, this is the number
+                             // of frames seen so far, with the last frame
+                             // possibly being partial.
 } WebPFormatFeature;
 
 // Get the 'feature' value from the 'dmux'.
 // NOTE: values are only valid if WebPDemux() was used or WebPDemuxPartial()
 // returned a state > WEBP_DEMUX_PARSING_HEADER.
-WEBP_EXTERN(uint32_t) WebPDemuxGetI(
+// If 'feature' is WEBP_FF_FORMAT_FLAGS, the returned value is a bit-wise
+// combination of WebPFeatureFlags values.
+// If 'feature' is WEBP_FF_LOOP_COUNT, WEBP_FF_BACKGROUND_COLOR, the returned
+// value is only meaningful if the bitstream is animated.
+WEBP_EXTERN uint32_t WebPDemuxGetI(
     const WebPDemuxer* dmux, WebPFormatFeature feature);
 
 //------------------------------------------------------------------------------
@@ -159,20 +164,20 @@ struct WebPIterator {
 // Returns false if 'dmux' is NULL or frame 'frame_number' is not present.
 // Call WebPDemuxReleaseIterator() when use of the iterator is complete.
 // NOTE: 'dmux' must persist for the lifetime of 'iter'.
-WEBP_EXTERN(int) WebPDemuxGetFrame(
+WEBP_EXTERN int WebPDemuxGetFrame(
     const WebPDemuxer* dmux, int frame_number, WebPIterator* iter);
 
 // Sets 'iter->fragment' to point to the next ('iter->frame_num' + 1) or
 // previous ('iter->frame_num' - 1) frame. These functions do not loop.
 // Returns true on success, false otherwise.
-WEBP_EXTERN(int) WebPDemuxNextFrame(WebPIterator* iter);
-WEBP_EXTERN(int) WebPDemuxPrevFrame(WebPIterator* iter);
+WEBP_EXTERN int WebPDemuxNextFrame(WebPIterator* iter);
+WEBP_EXTERN int WebPDemuxPrevFrame(WebPIterator* iter);
 
 // Releases any memory associated with 'iter'.
 // Must be called before any subsequent calls to WebPDemuxGetChunk() on the same
 // iter. Also, must be called before destroying the associated WebPDemuxer with
 // WebPDemuxDelete().
-WEBP_EXTERN(void) WebPDemuxReleaseIterator(WebPIterator* iter);
+WEBP_EXTERN void WebPDemuxReleaseIterator(WebPIterator* iter);
 
 //------------------------------------------------------------------------------
 // Chunk iteration.
@@ -197,20 +202,20 @@ struct WebPChunkIterator {
 // payloads are accessed through WebPDemuxGetFrame() and related functions.
 // Call WebPDemuxReleaseChunkIterator() when use of the iterator is complete.
 // NOTE: 'dmux' must persist for the lifetime of the iterator.
-WEBP_EXTERN(int) WebPDemuxGetChunk(const WebPDemuxer* dmux,
-                                   const char fourcc[4], int chunk_number,
-                                   WebPChunkIterator* iter);
+WEBP_EXTERN int WebPDemuxGetChunk(const WebPDemuxer* dmux,
+                                  const char fourcc[4], int chunk_number,
+                                  WebPChunkIterator* iter);
 
 // Sets 'iter->chunk' to point to the next ('iter->chunk_num' + 1) or previous
 // ('iter->chunk_num' - 1) chunk. These functions do not loop.
 // Returns true on success, false otherwise.
-WEBP_EXTERN(int) WebPDemuxNextChunk(WebPChunkIterator* iter);
-WEBP_EXTERN(int) WebPDemuxPrevChunk(WebPChunkIterator* iter);
+WEBP_EXTERN int WebPDemuxNextChunk(WebPChunkIterator* iter);
+WEBP_EXTERN int WebPDemuxPrevChunk(WebPChunkIterator* iter);
 
 // Releases any memory associated with 'iter'.
 // Must be called before destroying the associated WebPDemuxer with
 // WebPDemuxDelete().
-WEBP_EXTERN(void) WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter);
+WEBP_EXTERN void WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter);
 
 //------------------------------------------------------------------------------
 // WebPAnimDecoder API
@@ -252,7 +257,7 @@ struct WebPAnimDecoderOptions {
 };
 
 // Internal, version-checked, entry point.
-WEBP_EXTERN(int) WebPAnimDecoderOptionsInitInternal(
+WEBP_EXTERN int WebPAnimDecoderOptionsInitInternal(
     WebPAnimDecoderOptions*, int);
 
 // Should always be called, to initialize a fresh WebPAnimDecoderOptions
@@ -266,7 +271,7 @@ static WEBP_INLINE int WebPAnimDecoderOptionsInit(
 }
 
 // Internal, version-checked, entry point.
-WEBP_EXTERN(WebPAnimDecoder*) WebPAnimDecoderNewInternal(
+WEBP_EXTERN WebPAnimDecoder* WebPAnimDecoderNewInternal(
     const WebPData*, const WebPAnimDecoderOptions*, int);
 
 // Creates and initializes a WebPAnimDecoder object.
@@ -301,8 +306,8 @@ struct WebPAnimInfo {
 //   info - (out) global information fetched from the animation.
 // Returns:
 //   True on success.
-WEBP_EXTERN(int) WebPAnimDecoderGetInfo(const WebPAnimDecoder* dec,
-                                        WebPAnimInfo* info);
+WEBP_EXTERN int WebPAnimDecoderGetInfo(const WebPAnimDecoder* dec,
+                                       WebPAnimInfo* info);
 
 // Fetch the next frame from 'dec' based on options supplied to
 // WebPAnimDecoderNew(). This will be a fully reconstructed canvas of size
@@ -316,8 +321,8 @@ WEBP_EXTERN(int) WebPAnimDecoderGetInfo(const WebPAnimDecoder* dec,
 // Returns:
 //   False if any of the arguments are NULL, or if there is a parsing or
 //   decoding error, or if there are no more frames. Otherwise, returns true.
-WEBP_EXTERN(int) WebPAnimDecoderGetNext(WebPAnimDecoder* dec,
-                                        uint8_t** buf, int* timestamp);
+WEBP_EXTERN int WebPAnimDecoderGetNext(WebPAnimDecoder* dec,
+                                       uint8_t** buf, int* timestamp);
 
 // Check if there are more frames left to decode.
 // Parameters:
@@ -325,7 +330,7 @@ WEBP_EXTERN(int) WebPAnimDecoderGetNext(WebPAnimDecoder* dec,
 // Returns:
 //   True if 'dec' is not NULL and some frames are yet to be decoded.
 //   Otherwise, returns false.
-WEBP_EXTERN(int) WebPAnimDecoderHasMoreFrames(const WebPAnimDecoder* dec);
+WEBP_EXTERN int WebPAnimDecoderHasMoreFrames(const WebPAnimDecoder* dec);
 
 // Resets the WebPAnimDecoder object, so that next call to
 // WebPAnimDecoderGetNext() will restart decoding from 1st frame. This would be
@@ -333,7 +338,7 @@ WEBP_EXTERN(int) WebPAnimDecoderHasMoreFrames(const WebPAnimDecoder* dec);
 // info.loop_count times) without destroying and recreating the 'dec' object.
 // Parameters:
 //   dec - (in/out) decoder instance to be reset
-WEBP_EXTERN(void) WebPAnimDecoderReset(WebPAnimDecoder* dec);
+WEBP_EXTERN void WebPAnimDecoderReset(WebPAnimDecoder* dec);
 
 // Grab the internal demuxer object.
 // Getting the demuxer object can be useful if one wants to use operations only
@@ -343,13 +348,13 @@ WEBP_EXTERN(void) WebPAnimDecoderReset(WebPAnimDecoder* dec);
 //
 // Parameters:
 //   dec - (in) decoder instance from which the demuxer object is to be fetched.
-WEBP_EXTERN(const WebPDemuxer*) WebPAnimDecoderGetDemuxer(
+WEBP_EXTERN const WebPDemuxer* WebPAnimDecoderGetDemuxer(
     const WebPAnimDecoder* dec);
 
 // Deletes the WebPAnimDecoder object.
 // Parameters:
 //   dec - (in/out) decoder instance to be deleted
-WEBP_EXTERN(void) WebPAnimDecoderDelete(WebPAnimDecoder* dec);
+WEBP_EXTERN void WebPAnimDecoderDelete(WebPAnimDecoder* dec);
 
 #ifdef __cplusplus
 }    // extern "C"
diff --git a/media/libwebp/webp/encode.h b/media/libwebp/webp/encode.h
index 35fde1d05..7ec3543dc 100644
--- a/media/libwebp/webp/encode.h
+++ b/media/libwebp/webp/encode.h
@@ -35,7 +35,7 @@ typedef struct WebPMemoryWriter WebPMemoryWriter;
 
 // Return the encoder's version number, packed in hexadecimal using 8bits for
 // each of major/minor/revision. E.g: v2.5.7 is 0x020507.
-WEBP_EXTERN(int) WebPGetEncoderVersion(void);
+WEBP_EXTERN int WebPGetEncoderVersion(void);
 
 //------------------------------------------------------------------------------
 // One-stop-shop call! No questions asked:
@@ -46,37 +46,37 @@ WEBP_EXTERN(int) WebPGetEncoderVersion(void);
 // These functions compress using the lossy format, and the quality_factor
 // can go from 0 (smaller output, lower quality) to 100 (best quality,
 // larger output).
-WEBP_EXTERN(size_t) WebPEncodeRGB(const uint8_t* rgb,
+WEBP_EXTERN size_t WebPEncodeRGB(const uint8_t* rgb,
+                                 int width, int height, int stride,
+                                 float quality_factor, uint8_t** output);
+WEBP_EXTERN size_t WebPEncodeBGR(const uint8_t* bgr,
+                                 int width, int height, int stride,
+                                 float quality_factor, uint8_t** output);
+WEBP_EXTERN size_t WebPEncodeRGBA(const uint8_t* rgba,
                                   int width, int height, int stride,
                                   float quality_factor, uint8_t** output);
-WEBP_EXTERN(size_t) WebPEncodeBGR(const uint8_t* bgr,
+WEBP_EXTERN size_t WebPEncodeBGRA(const uint8_t* bgra,
                                   int width, int height, int stride,
                                   float quality_factor, uint8_t** output);
-WEBP_EXTERN(size_t) WebPEncodeRGBA(const uint8_t* rgba,
-                                   int width, int height, int stride,
-                                   float quality_factor, uint8_t** output);
-WEBP_EXTERN(size_t) WebPEncodeBGRA(const uint8_t* bgra,
-                                   int width, int height, int stride,
-                                   float quality_factor, uint8_t** output);
 
 // These functions are the equivalent of the above, but compressing in a
 // lossless manner. Files are usually larger than lossy format, but will
 // not suffer any compression loss.
-WEBP_EXTERN(size_t) WebPEncodeLosslessRGB(const uint8_t* rgb,
+WEBP_EXTERN size_t WebPEncodeLosslessRGB(const uint8_t* rgb,
+                                         int width, int height, int stride,
+                                         uint8_t** output);
+WEBP_EXTERN size_t WebPEncodeLosslessBGR(const uint8_t* bgr,
+                                         int width, int height, int stride,
+                                         uint8_t** output);
+WEBP_EXTERN size_t WebPEncodeLosslessRGBA(const uint8_t* rgba,
                                           int width, int height, int stride,
                                           uint8_t** output);
-WEBP_EXTERN(size_t) WebPEncodeLosslessBGR(const uint8_t* bgr,
+WEBP_EXTERN size_t WebPEncodeLosslessBGRA(const uint8_t* bgra,
                                           int width, int height, int stride,
                                           uint8_t** output);
-WEBP_EXTERN(size_t) WebPEncodeLosslessRGBA(const uint8_t* rgba,
-                                           int width, int height, int stride,
-                                           uint8_t** output);
-WEBP_EXTERN(size_t) WebPEncodeLosslessBGRA(const uint8_t* bgra,
-                                           int width, int height, int stride,
-                                           uint8_t** output);
 
 // Releases memory returned by the WebPEncode*() functions above.
-WEBP_EXTERN(void) WebPFree(void* ptr);
+WEBP_EXTERN void WebPFree(void* ptr);
 
 //------------------------------------------------------------------------------
 // Coding parameters
@@ -93,12 +93,15 @@ typedef enum WebPImageHint {
 // Compression parameters.
 struct WebPConfig {
   int lossless;           // Lossless encoding (0=lossy(default), 1=lossless).
-  float quality;          // between 0 (smallest file) and 100 (biggest)
+  float quality;          // between 0 and 100. For lossy, 0 gives the smallest
+                          // size and 100 the largest. For lossless, this
+                          // parameter is the amount of effort put into the
+                          // compression: 0 is the fastest but gives larger
+                          // files compared to the slowest, but best, 100.
   int method;             // quality/speed trade-off (0=fast, 6=slower-better)
 
   WebPImageHint image_hint;  // Hint for image type (lossless only for now).
 
-  // Parameters related to lossy compression only:
   int target_size;        // if non-zero, set the desired target size in bytes.
                           // Takes precedence over the 'compression' parameter.
   float target_PSNR;      // if non-zero, specifies the minimal distortion to
@@ -159,7 +162,7 @@ typedef enum WebPPreset {
 } WebPPreset;
 
 // Internal, version-checked, entry point
-WEBP_EXTERN(int) WebPConfigInitInternal(WebPConfig*, WebPPreset, float, int);
+WEBP_EXTERN int WebPConfigInitInternal(WebPConfig*, WebPPreset, float, int);
 
 // Should always be called, to initialize a fresh WebPConfig structure before
 // modification. Returns false in case of version mismatch. WebPConfigInit()
@@ -186,15 +189,15 @@ static WEBP_INLINE int WebPConfigPreset(WebPConfig* config,
 // speed and final compressed size.
 // This function will overwrite several fields from config: 'method', 'quality'
 // and 'lossless'. Returns false in case of parameter error.
-WEBP_EXTERN(int) WebPConfigLosslessPreset(WebPConfig* config, int level);
+WEBP_EXTERN int WebPConfigLosslessPreset(WebPConfig* config, int level);
 
 // Returns true if 'config' is non-NULL and all configuration parameters are
 // within their valid ranges.
-WEBP_EXTERN(int) WebPValidateConfig(const WebPConfig* config);
+WEBP_EXTERN int WebPValidateConfig(const WebPConfig* config);
 
 //------------------------------------------------------------------------------
 // Input / Output
-// Structure for storing auxiliary statistics (mostly for lossy encoding).
+// Structure for storing auxiliary statistics.
 
 struct WebPAuxStats {
   int coded_size;         // final size
@@ -242,16 +245,16 @@ struct WebPMemoryWriter {
 };
 
 // The following must be called first before any use.
-WEBP_EXTERN(void) WebPMemoryWriterInit(WebPMemoryWriter* writer);
+WEBP_EXTERN void WebPMemoryWriterInit(WebPMemoryWriter* writer);
 
 // The following must be called to deallocate writer->mem memory. The 'writer'
 // object itself is not deallocated.
-WEBP_EXTERN(void) WebPMemoryWriterClear(WebPMemoryWriter* writer);
+WEBP_EXTERN void WebPMemoryWriterClear(WebPMemoryWriter* writer);
 // The custom writer to be used with WebPMemoryWriter as custom_ptr. Upon
 // completion, writer.mem and writer.size will hold the coded data.
 // writer.mem must be freed by calling WebPMemoryWriterClear.
-WEBP_EXTERN(int) WebPMemoryWrite(const uint8_t* data, size_t data_size,
-                                 const WebPPicture* picture);
+WEBP_EXTERN int WebPMemoryWrite(const uint8_t* data, size_t data_size,
+                                const WebPPicture* picture);
 
 // Progress hook, called from time to time to report progress. It can return
 // false to request an abort of the encoding process, or true otherwise if
@@ -354,7 +357,7 @@ struct WebPPicture {
 };
 
 // Internal, version-checked, entry point
-WEBP_EXTERN(int) WebPPictureInitInternal(WebPPicture*, int);
+WEBP_EXTERN int WebPPictureInitInternal(WebPPicture*, int);
 
 // Should always be called, to initialize the structure. Returns false in case
 // of version mismatch. WebPPictureInit() must have succeeded before using the
@@ -371,20 +374,20 @@ static WEBP_INLINE int WebPPictureInit(WebPPicture* picture) {
 // Allocate y/u/v buffers as per colorspace/width/height specification.
 // Note! This function will free the previous buffer if needed.
 // Returns false in case of memory error.
-WEBP_EXTERN(int) WebPPictureAlloc(WebPPicture* picture);
+WEBP_EXTERN int WebPPictureAlloc(WebPPicture* picture);
 
 // Release the memory allocated by WebPPictureAlloc() or WebPPictureImport*().
 // Note that this function does _not_ free the memory used by the 'picture'
 // object itself.
 // Besides memory (which is reclaimed) all other fields of 'picture' are
 // preserved.
-WEBP_EXTERN(void) WebPPictureFree(WebPPicture* picture);
+WEBP_EXTERN void WebPPictureFree(WebPPicture* picture);
 
 // Copy the pixels of *src into *dst, using WebPPictureAlloc. Upon return, *dst
 // will fully own the copied pixels (this is not a view). The 'dst' picture need
 // not be initialized as its content is overwritten.
 // Returns false in case of memory allocation error.
-WEBP_EXTERN(int) WebPPictureCopy(const WebPPicture* src, WebPPicture* dst);
+WEBP_EXTERN int WebPPictureCopy(const WebPPicture* src, WebPPicture* dst);
 
 // Compute the single distortion for packed planes of samples.
 // 'src' will be compared to 'ref', and the raw distortion stored into
@@ -393,19 +396,19 @@ WEBP_EXTERN(int) WebPPictureCopy(const WebPPicture* src, WebPPicture* dst);
 // 'x_step' is the horizontal stride (in bytes) between samples.
 // 'src/ref_stride' is the byte distance between rows.
 // Returns false in case of error (bad parameter, memory allocation error, ...).
-WEBP_EXTERN(int) WebPPlaneDistortion(const uint8_t* src, size_t src_stride,
-                                     const uint8_t* ref, size_t ref_stride,
-                                     int width, int height,
-                                     size_t x_step,
-                                     int type,   // 0 = PSNR, 1 = SSIM, 2 = LSIM
-                                     float* distortion, float* result);
+WEBP_EXTERN int WebPPlaneDistortion(const uint8_t* src, size_t src_stride,
+                                    const uint8_t* ref, size_t ref_stride,
+                                    int width, int height,
+                                    size_t x_step,
+                                    int type,   // 0 = PSNR, 1 = SSIM, 2 = LSIM
+                                    float* distortion, float* result);
 
 // Compute PSNR, SSIM or LSIM distortion metric between two pictures. Results
 // are in dB, stored in result[] in the B/G/R/A/All order. The distortion is
 // always performed using ARGB samples. Hence if the input is YUV(A), the
 // picture will be internally converted to ARGB (just for the measurement).
 // Warning: this function is rather CPU-intensive.
-WEBP_EXTERN(int) WebPPictureDistortion(
+WEBP_EXTERN int WebPPictureDistortion(
     const WebPPicture* src, const WebPPicture* ref,
     int metric_type,           // 0 = PSNR, 1 = SSIM, 2 = LSIM
     float result[5]);
@@ -418,8 +421,8 @@ WEBP_EXTERN(int) WebPPictureDistortion(
 // must be fully be comprised inside the 'src' source picture. If the source
 // picture uses the YUV420 colorspace, the top and left coordinates will be
 // snapped to even values.
-WEBP_EXTERN(int) WebPPictureCrop(WebPPicture* picture,
-                                 int left, int top, int width, int height);
+WEBP_EXTERN int WebPPictureCrop(WebPPicture* picture,
+                                int left, int top, int width, int height);
 
 // Extracts a view from 'src' picture into 'dst'. The rectangle for the view
 // is defined by the top-left corner pixel coordinates (left, top) as well
@@ -432,42 +435,42 @@ WEBP_EXTERN(int) WebPPictureCrop(WebPPicture* picture,
 // with WebPPictureInit() if it is different from 'src', since its content will
 // be overwritten.
 // Returns false in case of memory allocation error or invalid parameters.
-WEBP_EXTERN(int) WebPPictureView(const WebPPicture* src,
-                                 int left, int top, int width, int height,
-                                 WebPPicture* dst);
+WEBP_EXTERN int WebPPictureView(const WebPPicture* src,
+                                int left, int top, int width, int height,
+                                WebPPicture* dst);
 
 // Returns true if the 'picture' is actually a view and therefore does
 // not own the memory for pixels.
-WEBP_EXTERN(int) WebPPictureIsView(const WebPPicture* picture);
+WEBP_EXTERN int WebPPictureIsView(const WebPPicture* picture);
 
 // Rescale a picture to new dimension width x height.
 // If either 'width' or 'height' (but not both) is 0 the corresponding
 // dimension will be calculated preserving the aspect ratio.
 // No gamma correction is applied.
 // Returns false in case of error (invalid parameter or insufficient memory).
-WEBP_EXTERN(int) WebPPictureRescale(WebPPicture* pic, int width, int height);
+WEBP_EXTERN int WebPPictureRescale(WebPPicture* pic, int width, int height);
 
 // Colorspace conversion function to import RGB samples.
 // Previous buffer will be free'd, if any.
 // *rgb buffer should have a size of at least height * rgb_stride.
 // Returns false in case of memory error.
-WEBP_EXTERN(int) WebPPictureImportRGB(
+WEBP_EXTERN int WebPPictureImportRGB(
     WebPPicture* picture, const uint8_t* rgb, int rgb_stride);
 // Same, but for RGBA buffer.
-WEBP_EXTERN(int) WebPPictureImportRGBA(
+WEBP_EXTERN int WebPPictureImportRGBA(
     WebPPicture* picture, const uint8_t* rgba, int rgba_stride);
 // Same, but for RGBA buffer. Imports the RGB direct from the 32-bit format
 // input buffer ignoring the alpha channel. Avoids needing to copy the data
 // to a temporary 24-bit RGB buffer to import the RGB only.
-WEBP_EXTERN(int) WebPPictureImportRGBX(
+WEBP_EXTERN int WebPPictureImportRGBX(
     WebPPicture* picture, const uint8_t* rgbx, int rgbx_stride);
 
 // Variants of the above, but taking BGR(A|X) input.
-WEBP_EXTERN(int) WebPPictureImportBGR(
+WEBP_EXTERN int WebPPictureImportBGR(
     WebPPicture* picture, const uint8_t* bgr, int bgr_stride);
-WEBP_EXTERN(int) WebPPictureImportBGRA(
+WEBP_EXTERN int WebPPictureImportBGRA(
     WebPPicture* picture, const uint8_t* bgra, int bgra_stride);
-WEBP_EXTERN(int) WebPPictureImportBGRX(
+WEBP_EXTERN int WebPPictureImportBGRX(
     WebPPicture* picture, const uint8_t* bgrx, int bgrx_stride);
 
 // Converts picture->argb data to the YUV420A format. The 'colorspace'
@@ -476,14 +479,14 @@ WEBP_EXTERN(int) WebPPictureImportBGRX(
 // non-opaque transparent values is detected, and 'colorspace' will be
 // adjusted accordingly. Note that this method is lossy.
 // Returns false in case of error.
-WEBP_EXTERN(int) WebPPictureARGBToYUVA(WebPPicture* picture,
-                                       WebPEncCSP /*colorspace = WEBP_YUV420*/);
+WEBP_EXTERN int WebPPictureARGBToYUVA(WebPPicture* picture,
+                                      WebPEncCSP /*colorspace = WEBP_YUV420*/);
 
 // Same as WebPPictureARGBToYUVA(), but the conversion is done using
 // pseudo-random dithering with a strength 'dithering' between
 // 0.0 (no dithering) and 1.0 (maximum dithering). This is useful
 // for photographic picture.
-WEBP_EXTERN(int) WebPPictureARGBToYUVADithered(
+WEBP_EXTERN int WebPPictureARGBToYUVADithered(
     WebPPicture* picture, WebPEncCSP colorspace, float dithering);
 
 // Performs 'sharp' RGBA->YUVA420 downsampling and colorspace conversion.
@@ -491,9 +494,9 @@ WEBP_EXTERN(int) WebPPictureARGBToYUVADithered(
 // method is roughly 2x slower than WebPPictureARGBToYUVA() but produces better
 // and sharper YUV representation.
 // Returns false in case of error.
-WEBP_EXTERN(int) WebPPictureSharpARGBToYUVA(WebPPicture* picture);
+WEBP_EXTERN int WebPPictureSharpARGBToYUVA(WebPPicture* picture);
 // kept for backward compatibility:
-WEBP_EXTERN(int) WebPPictureSmartARGBToYUVA(WebPPicture* picture);
+WEBP_EXTERN int WebPPictureSmartARGBToYUVA(WebPPicture* picture);
 
 // Converts picture->yuv to picture->argb and sets picture->use_argb to true.
 // The input format must be YUV_420 or YUV_420A. The conversion from YUV420 to
@@ -501,22 +504,22 @@ WEBP_EXTERN(int) WebPPictureSmartARGBToYUVA(WebPPicture* picture);
 // Note that the use of this colorspace is discouraged if one has access to the
 // raw ARGB samples, since using YUV420 is comparatively lossy.
 // Returns false in case of error.
-WEBP_EXTERN(int) WebPPictureYUVAToARGB(WebPPicture* picture);
+WEBP_EXTERN int WebPPictureYUVAToARGB(WebPPicture* picture);
 
 // Helper function: given a width x height plane of RGBA or YUV(A) samples
-// clean-up the YUV or RGB samples under fully transparent area, to help
-// compressibility (no guarantee, though).
-WEBP_EXTERN(void) WebPCleanupTransparentArea(WebPPicture* picture);
+// clean-up or smoothen the YUV or RGB samples under fully transparent area,
+// to help compressibility (no guarantee, though).
+WEBP_EXTERN void WebPCleanupTransparentArea(WebPPicture* picture);
 
 // Scan the picture 'picture' for the presence of non fully opaque alpha values.
 // Returns true in such case. Otherwise returns false (indicating that the
 // alpha plane can be ignored altogether e.g.).
-WEBP_EXTERN(int) WebPPictureHasTransparency(const WebPPicture* picture);
+WEBP_EXTERN int WebPPictureHasTransparency(const WebPPicture* picture);
 
 // Remove the transparency information (if present) by blending the color with
 // the background color 'background_rgb' (specified as 24bit RGB triplet).
 // After this call, all alpha values are reset to 0xff.
-WEBP_EXTERN(void) WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb);
+WEBP_EXTERN void WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb);
 
 //------------------------------------------------------------------------------
 // Main call
@@ -531,7 +534,7 @@ WEBP_EXTERN(void) WebPBlendAlpha(WebPPicture* pic, uint32_t background_rgb);
 // the former for lossy encoding, and the latter for lossless encoding
 // (when config.lossless is true). Automatic conversion from one format to
 // another is provided but they both incur some loss.
-WEBP_EXTERN(int) WebPEncode(const WebPConfig* config, WebPPicture* picture);
+WEBP_EXTERN int WebPEncode(const WebPConfig* config, WebPPicture* picture);
 
 //------------------------------------------------------------------------------
 
diff --git a/media/libwebp/webp/mux.h b/media/libwebp/webp/mux.h
index daccc65e8..28bb4a41c 100644
--- a/media/libwebp/webp/mux.h
+++ b/media/libwebp/webp/mux.h
@@ -98,13 +98,13 @@ typedef enum WebPChunkId {
 
 // Returns the version number of the mux library, packed in hexadecimal using
 // 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507.
-WEBP_EXTERN(int) WebPGetMuxVersion(void);
+WEBP_EXTERN int WebPGetMuxVersion(void);
 
 //------------------------------------------------------------------------------
 // Life of a Mux object
 
 // Internal, version-checked, entry point
-WEBP_EXTERN(WebPMux*) WebPNewInternal(int);
+WEBP_EXTERN WebPMux* WebPNewInternal(int);
 
 // Creates an empty mux object.
 // Returns:
@@ -117,13 +117,13 @@ static WEBP_INLINE WebPMux* WebPMuxNew(void) {
 // Deletes the mux object.
 // Parameters:
 //   mux - (in/out) object to be deleted
-WEBP_EXTERN(void) WebPMuxDelete(WebPMux* mux);
+WEBP_EXTERN void WebPMuxDelete(WebPMux* mux);
 
 //------------------------------------------------------------------------------
 // Mux creation.
 
 // Internal, version-checked, entry point
-WEBP_EXTERN(WebPMux*) WebPMuxCreateInternal(const WebPData*, int, int);
+WEBP_EXTERN WebPMux* WebPMuxCreateInternal(const WebPData*, int, int);
 
 // Creates a mux object from raw data given in WebP RIFF format.
 // Parameters:
@@ -160,7 +160,7 @@ static WEBP_INLINE WebPMux* WebPMuxCreate(const WebPData* bitstream,
 //                               or if fourcc corresponds to an image chunk.
 //   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxSetChunk(
+WEBP_EXTERN WebPMuxError WebPMuxSetChunk(
     WebPMux* mux, const char fourcc[4], const WebPData* chunk_data,
     int copy_data);
 
@@ -176,7 +176,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxSetChunk(
 //                               or if fourcc corresponds to an image chunk.
 //   WEBP_MUX_NOT_FOUND - If mux does not contain a chunk with the given id.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxGetChunk(
+WEBP_EXTERN WebPMuxError WebPMuxGetChunk(
     const WebPMux* mux, const char fourcc[4], WebPData* chunk_data);
 
 // Deletes the chunk with the given 'fourcc' from the mux object.
@@ -189,7 +189,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxGetChunk(
 //                               or if fourcc corresponds to an image chunk.
 //   WEBP_MUX_NOT_FOUND - If mux does not contain a chunk with the given fourcc.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxDeleteChunk(
+WEBP_EXTERN WebPMuxError WebPMuxDeleteChunk(
     WebPMux* mux, const char fourcc[4]);
 
 //------------------------------------------------------------------------------
@@ -222,7 +222,7 @@ struct WebPMuxFrameInfo {
 //   WEBP_MUX_INVALID_ARGUMENT - if mux is NULL or bitstream is NULL.
 //   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxSetImage(
+WEBP_EXTERN WebPMuxError WebPMuxSetImage(
     WebPMux* mux, const WebPData* bitstream, int copy_data);
 
 // Adds a frame at the end of the mux object.
@@ -241,7 +241,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxSetImage(
 //                               or if content of 'frame' is invalid.
 //   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxPushFrame(
+WEBP_EXTERN WebPMuxError WebPMuxPushFrame(
     WebPMux* mux, const WebPMuxFrameInfo* frame, int copy_data);
 
 // Gets the nth frame from the mux object.
@@ -259,7 +259,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxPushFrame(
 //   WEBP_MUX_BAD_DATA - if nth frame chunk in mux is invalid.
 //   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxGetFrame(
+WEBP_EXTERN WebPMuxError WebPMuxGetFrame(
     const WebPMux* mux, uint32_t nth, WebPMuxFrameInfo* frame);
 
 // Deletes a frame from the mux object.
@@ -272,7 +272,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxGetFrame(
 //   WEBP_MUX_NOT_FOUND - If there are less than nth frames in the mux object
 //                        before deletion.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxDeleteFrame(WebPMux* mux, uint32_t nth);
+WEBP_EXTERN WebPMuxError WebPMuxDeleteFrame(WebPMux* mux, uint32_t nth);
 
 //------------------------------------------------------------------------------
 // Animation.
@@ -296,7 +296,7 @@ struct WebPMuxAnimParams {
 //   WEBP_MUX_INVALID_ARGUMENT - if mux or params is NULL.
 //   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxSetAnimationParams(
+WEBP_EXTERN WebPMuxError WebPMuxSetAnimationParams(
     WebPMux* mux, const WebPMuxAnimParams* params);
 
 // Gets the animation parameters from the mux object.
@@ -307,7 +307,7 @@ WEBP_EXTERN(WebPMuxError) WebPMuxSetAnimationParams(
 //   WEBP_MUX_INVALID_ARGUMENT - if mux or params is NULL.
 //   WEBP_MUX_NOT_FOUND - if ANIM chunk is not present in mux object.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxGetAnimationParams(
+WEBP_EXTERN WebPMuxError WebPMuxGetAnimationParams(
     const WebPMux* mux, WebPMuxAnimParams* params);
 
 //------------------------------------------------------------------------------
@@ -328,8 +328,8 @@ WEBP_EXTERN(WebPMuxError) WebPMuxGetAnimationParams(
 //   WEBP_MUX_INVALID_ARGUMENT - if mux is NULL; or
 //                               width or height are invalid or out of bounds
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxSetCanvasSize(WebPMux* mux,
-                                               int width, int height);
+WEBP_EXTERN WebPMuxError WebPMuxSetCanvasSize(WebPMux* mux,
+                                              int width, int height);
 
 // Gets the canvas size from the mux object.
 // Note: This method assumes that the VP8X chunk, if present, is up-to-date.
@@ -343,8 +343,8 @@ WEBP_EXTERN(WebPMuxError) WebPMuxSetCanvasSize(WebPMux* mux,
 //   WEBP_MUX_INVALID_ARGUMENT - if mux, width or height is NULL.
 //   WEBP_MUX_BAD_DATA - if VP8X/VP8/VP8L chunk or canvas size is invalid.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxGetCanvasSize(const WebPMux* mux,
-                                               int* width, int* height);
+WEBP_EXTERN WebPMuxError WebPMuxGetCanvasSize(const WebPMux* mux,
+                                              int* width, int* height);
 
 // Gets the feature flags from the mux object.
 // Note: This method assumes that the VP8X chunk, if present, is up-to-date.
@@ -359,8 +359,8 @@ WEBP_EXTERN(WebPMuxError) WebPMuxGetCanvasSize(const WebPMux* mux,
 //   WEBP_MUX_INVALID_ARGUMENT - if mux or flags is NULL.
 //   WEBP_MUX_BAD_DATA - if VP8X/VP8/VP8L chunk or canvas size is invalid.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxGetFeatures(const WebPMux* mux,
-                                             uint32_t* flags);
+WEBP_EXTERN WebPMuxError WebPMuxGetFeatures(const WebPMux* mux,
+                                            uint32_t* flags);
 
 // Gets number of chunks with the given 'id' in the mux object.
 // Parameters:
@@ -370,8 +370,8 @@ WEBP_EXTERN(WebPMuxError) WebPMuxGetFeatures(const WebPMux* mux,
 // Returns:
 //   WEBP_MUX_INVALID_ARGUMENT - if mux, or num_elements is NULL.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxNumChunks(const WebPMux* mux,
-                                           WebPChunkId id, int* num_elements);
+WEBP_EXTERN WebPMuxError WebPMuxNumChunks(const WebPMux* mux,
+                                          WebPChunkId id, int* num_elements);
 
 // Assembles all chunks in WebP RIFF format and returns in 'assembled_data'.
 // This function also validates the mux object.
@@ -388,8 +388,8 @@ WEBP_EXTERN(WebPMuxError) WebPMuxNumChunks(const WebPMux* mux,
 //   WEBP_MUX_INVALID_ARGUMENT - if mux or assembled_data is NULL.
 //   WEBP_MUX_MEMORY_ERROR - on memory allocation error.
 //   WEBP_MUX_OK - on success.
-WEBP_EXTERN(WebPMuxError) WebPMuxAssemble(WebPMux* mux,
-                                          WebPData* assembled_data);
+WEBP_EXTERN WebPMuxError WebPMuxAssemble(WebPMux* mux,
+                                         WebPData* assembled_data);
 
 //------------------------------------------------------------------------------
 // WebPAnimEncoder API
@@ -442,7 +442,7 @@ struct WebPAnimEncoderOptions {
 };
 
 // Internal, version-checked, entry point.
-WEBP_EXTERN(int) WebPAnimEncoderOptionsInitInternal(
+WEBP_EXTERN int WebPAnimEncoderOptionsInitInternal(
     WebPAnimEncoderOptions*, int);
 
 // Should always be called, to initialize a fresh WebPAnimEncoderOptions
@@ -455,7 +455,7 @@ static WEBP_INLINE int WebPAnimEncoderOptionsInit(
 }
 
 // Internal, version-checked, entry point.
-WEBP_EXTERN(WebPAnimEncoder*) WebPAnimEncoderNewInternal(
+WEBP_EXTERN WebPAnimEncoder* WebPAnimEncoderNewInternal(
     int, int, const WebPAnimEncoderOptions*, int);
 
 // Creates and initializes a WebPAnimEncoder object.
@@ -490,7 +490,7 @@ static WEBP_INLINE WebPAnimEncoder* WebPAnimEncoderNew(
 // Returns:
 //   On error, returns false and frame->error_code is set appropriately.
 //   Otherwise, returns true.
-WEBP_EXTERN(int) WebPAnimEncoderAdd(
+WEBP_EXTERN int WebPAnimEncoderAdd(
     WebPAnimEncoder* enc, struct WebPPicture* frame, int timestamp_ms,
     const struct WebPConfig* config);
 
@@ -503,8 +503,8 @@ WEBP_EXTERN(int) WebPAnimEncoderAdd(
 //   webp_data - (out) generated WebP bitstream.
 // Returns:
 //   True on success.
-WEBP_EXTERN(int) WebPAnimEncoderAssemble(WebPAnimEncoder* enc,
-                                         WebPData* webp_data);
+WEBP_EXTERN int WebPAnimEncoderAssemble(WebPAnimEncoder* enc,
+                                        WebPData* webp_data);
 
 // Get error string corresponding to the most recent call using 'enc'. The
 // returned string is owned by 'enc' and is valid only until the next call to
@@ -514,12 +514,12 @@ WEBP_EXTERN(int) WebPAnimEncoderAssemble(WebPAnimEncoder* enc,
 // Returns:
 //   NULL if 'enc' is NULL. Otherwise, returns the error string if the last call
 //   to 'enc' had an error, or an empty string if the last call was a success.
-WEBP_EXTERN(const char*) WebPAnimEncoderGetError(WebPAnimEncoder* enc);
+WEBP_EXTERN const char* WebPAnimEncoderGetError(WebPAnimEncoder* enc);
 
 // Deletes the WebPAnimEncoder object.
 // Parameters:
 //   enc - (in/out) object to be deleted
-WEBP_EXTERN(void) WebPAnimEncoderDelete(WebPAnimEncoder* enc);
+WEBP_EXTERN void WebPAnimEncoderDelete(WebPAnimEncoder* enc);
 
 //------------------------------------------------------------------------------
 
diff --git a/media/libwebp/webp/types.h b/media/libwebp/webp/types.h
index 98fff35a1..989a763f0 100644
--- a/media/libwebp/webp/types.h
+++ b/media/libwebp/webp/types.h
@@ -40,9 +40,9 @@ typedef long long int int64_t;
 // This explicitly marks library functions and allows for changing the
 // signature for e.g., Windows DLL builds.
 # if defined(__GNUC__) && __GNUC__ >= 4
-#  define WEBP_EXTERN(type) extern __attribute__ ((visibility ("default"))) type
+#  define WEBP_EXTERN extern __attribute__ ((visibility ("default")))
 # else
-#  define WEBP_EXTERN(type) extern type
+#  define WEBP_EXTERN extern
 # endif  /* __GNUC__ >= 4 */
 #endif  /* WEBP_EXTERN */