1 files changed, 97 insertions, 0 deletions
diff --git a/layout/base/MobileViewportManager.h b/layout/base/MobileViewportManager.h
new file mode 100644
index 000000000..63128b281
--- /dev/null
+++ b/layout/base/MobileViewportManager.h
@@ -0,0 +1,97 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MobileViewportManager_h_
+#define MobileViewportManager_h_
+
+#include "mozilla/Maybe.h"
+#include "nsIDOMEventListener.h"
+#include "nsIObserver.h"
+#include "Units.h"
+
+class nsIDOMEventTarget;
+class nsIDocument;
+class nsIPresShell;
+
+class MobileViewportManager final : public nsIDOMEventListener
+                                  , public nsIObserver
+{
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDOMEVENTLISTENER
+  NS_DECL_NSIOBSERVER
+
+  MobileViewportManager(nsIPresShell* aPresShell,
+                        nsIDocument* aDocument);
+  void Destroy();
+
+  /* Provide a resolution to use during the first paint instead of the default
+   * resolution computed from the viewport info metadata. This is in the same
+   * "units" as the argument to nsDOMWindowUtils::SetResolutionAndScaleTo.
+   * Also takes the previous display dimensions as they were at the time the
+   * resolution was stored in order to correctly adjust the resolution if the
+   * device was rotated in the meantime. */
+  void SetRestoreResolution(float aResolution,
+                            mozilla::LayoutDeviceIntSize aDisplaySize);
+
+  /* Notify the MobileViewportManager that a reflow was requested in the
+   * presShell.*/
+  void RequestReflow();
+
+  /* Notify the MobileViewportManager that the resolution on the presShell was
+   * updated, and the SPCSPS needs to be updated. */
+  void ResolutionUpdated();
+
+private:
+  ~MobileViewportManager();
+
+  /* Called to compute the initial viewport on page load or before-first-paint,
+   * whichever happens first. */
+  void SetInitialViewport();
+
+  /* Main helper method to update the CSS viewport and any other properties that
+   * need updating. */
+  void RefreshViewportSize(bool aForceAdjustResolution);
+
+  /* Secondary main helper method to update just the SPCSPS. */
+  void RefreshSPCSPS();
+
+  /* Helper to clamp the given zoom by the min/max in the viewport info. */
+  mozilla::CSSToScreenScale ClampZoom(const mozilla::CSSToScreenScale& aZoom,
+                                      const nsViewportInfo& aViewportInfo);
+
+  /* Helper to update the given resolution according to changed display and viewport widths. */
+  mozilla::LayoutDeviceToLayerScale
+  ScaleResolutionWithDisplayWidth(const mozilla::LayoutDeviceToLayerScale& aRes,
+                                  const float& aDisplayWidthChangeRatio,
+                                  const mozilla::CSSSize& aNewViewport,
+                                  const mozilla::CSSSize& aOldViewport);
+
+  /* Updates the presShell resolution and returns the new zoom. */
+  mozilla::CSSToScreenScale UpdateResolution(const nsViewportInfo& aViewportInfo,
+                                             const mozilla::ScreenIntSize& aDisplaySize,
+                                             const mozilla::CSSSize& aViewport,
+                                             const mozilla::Maybe<float>& aDisplayWidthChangeRatio);
+
+  /* Updates the scroll-position-clamping scrollport size */
+  void UpdateSPCSPS(const mozilla::ScreenIntSize& aDisplaySize,
+                    const mozilla::CSSToScreenScale& aZoom);
+
+  /* Updates the displayport margins for the presShell's root scrollable frame */
+  void UpdateDisplayPortMargins();
+
+  nsCOMPtr<nsIDocument> mDocument;
+  nsIPresShell* MOZ_NON_OWNING_REF mPresShell; // raw ref since the presShell owns this
+  nsCOMPtr<nsIDOMEventTarget> mEventTarget;
+  bool mIsFirstPaint;
+  bool mPainted;
+  mozilla::LayoutDeviceIntSize mDisplaySize;
+  mozilla::CSSSize mMobileViewportSize;
+  mozilla::Maybe<float> mRestoreResolution;
+  mozilla::Maybe<mozilla::ScreenIntSize> mRestoreDisplaySize;
+};
+
+#endif
+