Implement transform/clip support for Android WebView.

cc/output/output_surface.cc

 // Copyright (c) 2013 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.
 
 #include "cc/output/output_surface.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 28 matching lines @@
   virtual void onContextLost() { client_->DidLoseOutputSurface(); }
 
  private:
   OutputSurfaceClient* client_;
 };
 
 OutputSurface::OutputSurface(
     scoped_ptr<WebKit::WebGraphicsContext3D> context3d)
     : client_(NULL),
       context3d_(context3d.Pass()),
-      has_gl_discard_backbuffer_(false) {
+      has_gl_discard_backbuffer_(false),
+      device_scale_factor_(-1) {
 }
 
 OutputSurface::OutputSurface(
     scoped_ptr<cc::SoftwareOutputDevice> software_device)
     : client_(NULL),
       software_device_(software_device.Pass()),
-      has_gl_discard_backbuffer_(false) {
+      has_gl_discard_backbuffer_(false),
+      device_scale_factor_(-1) {
 }
 
 OutputSurface::OutputSurface(
     scoped_ptr<WebKit::WebGraphicsContext3D> context3d,
     scoped_ptr<cc::SoftwareOutputDevice> software_device)
     : client_(NULL),
       context3d_(context3d.Pass()),
       software_device_(software_device.Pass()),
-      has_gl_discard_backbuffer_(false) {
+      has_gl_discard_backbuffer_(false),
+      device_scale_factor_(-1) {
 }
 
 OutputSurface::~OutputSurface() {
 }
 
 bool OutputSurface::ForcedDrawToSoftwareDevice() const {
   return false;
 }
 
 bool OutputSurface::BindToClient(
@@ skipping 29 matching lines @@
     context3d_->ensureBackbufferCHROMIUM();
 }
 
 void OutputSurface::DiscardBackbuffer() {
   DCHECK(context3d_);
   if (has_gl_discard_backbuffer_)
     context3d_->discardBackbufferCHROMIUM();
 }
 
 void OutputSurface::Reshape(gfx::Size size, float scale_factor) {
-  DCHECK(context3d_);
-  context3d_->reshapeWithScaleFactor(size.width(), size.height(), scale_factor);
+  if (size == surface_size_ && scale_factor == device_scale_factor_)
+    return;
+
+  surface_size_ = size;
+  device_scale_factor_ = scale_factor;
+  if (context3d_) {
+    context3d_->reshapeWithScaleFactor(
+        size.width(), size.height(), scale_factor);
+  }
+}
+
+gfx::Size OutputSurface::SurfaceSize() const {
+  return surface_size_;
 }
 
 void OutputSurface::BindFramebuffer() {
   DCHECK(context3d_);
   context3d_->bindFramebuffer(GL_FRAMEBUFFER, 0);
 }
 
 void OutputSurface::SwapBuffers(const ui::LatencyInfo& latency_info) {
   DCHECK(context3d_);
   // Note that currently this has the same effect as SwapBuffers; we should
   // consider exposing a different entry point on WebGraphicsContext3D.
   context3d_->prepareTexture();
 }
 
 void OutputSurface::PostSubBuffer(gfx::Rect rect,
                                   const ui::LatencyInfo& latency_info) {
   DCHECK(context3d_);
   context3d_->postSubBufferCHROMIUM(
       rect.x(), rect.y(), rect.width(), rect.height());
 }
 
 }  // namespace cc