Implement overscroll support for the virtual keyboard.

content/public/browser/render_widget_host_view.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_H_
 #define CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_H_
 
 #include "base/basictypes.h"
 #include "base/strings/string16.h"
 #include "content/common/content_export.h"
@@ skipping 96 matching lines @@
   // the custom background for their platform.
   virtual void SetBackground(const SkBitmap& background) = 0;
   virtual const SkBitmap& GetBackground() = 0;
 
   // Return value indicates whether the mouse is locked successfully or not.
   virtual bool LockMouse() = 0;
   virtual void UnlockMouse() = 0;
   // Returns true if the mouse pointer is currently locked.
   virtual bool IsMouseLocked() = 0;
 
+  // Retrives the size of the viewport for the visible region. May be smaller
+  // than the view size if a portion of the view is obstructed (e.g. by a
+  // virtual keyboard).
+  virtual gfx::SizeF GetVisibleViewportSize() const = 0;

[sky, 2014/04/24 15:55:09]

Why is this floating point when nothing else in this class is?

[kevers, 2014/04/24 18:38:33]

Based on suggestion by aelias.  Android makes significant use of floating point
scale factors (e.g. overdraw_bottom_height).  Currently, we have rounding on
both the browser side and Blink. The suggestion to use float is based on the
direction Android seems to be moving. Switching  to integer for now as it can
always be changed to float later as needed.

+
+  // Set insets for the visible region of the root window. Used to compute the
+  // visible viewport.
+  virtual void SetInsets(const gfx::Insets& insets) = 0;
+
 #if defined(OS_MACOSX)
   // Set the view's active state (i.e., tint state of controls).
   virtual void SetActive(bool active) = 0;
 
   // Tells the view whether or not to accept first responder status.  If |flag|
   // is true, the view does not accept first responder status and instead
   // manually becomes first responder when it receives a mouse down event.  If
   // |flag| is false, the view participates in the key-view chain as normal.
   virtual void SetTakesFocusOnlyOnMouseDown(bool flag) = 0;
 
@@ skipping 18 matching lines @@
   // Returns |true| if text is currently being spoken by Mac OS X.
   virtual bool IsSpeaking() const = 0;
   // Stops speaking, if it is currently in progress.
   virtual void StopSpeaking() = 0;
 #endif  // defined(OS_MACOSX)
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_RENDER_WIDGET_HOST_VIEW_H_