Adds support for capturing a sub rect of the compositing surface.

content/browser/renderer_host/render_widget_host_view_android.cc

 // 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_android.h"
 
 #include <android/bitmap.h>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
@@ skipping 235 matching lines @@
   default_size_ = size;
   WasResized();
 }
 
 void RenderWidgetHostViewAndroid::SetBounds(const gfx::Rect& rect) {
   SetSize(rect.size());
 }
 
 void RenderWidgetHostViewAndroid::GetScaledContentBitmap(
     float scale,
+    gfx::Rect src_subrect,

[powei, 2014/02/22 02:06:32]

Can you add a dcheck to make sure that src_subrect is inside the bounds of the
layer?

[clholgat, 2014/02/24 17:15:56]

Done.

     gfx::Size* out_size,
     const base::Callback<void(bool, const SkBitmap&)>& result_callback) {
   if (!IsSurfaceAvailableForCopy()) {
     result_callback.Run(false, SkBitmap());
     return;
   }
 
   gfx::Size bounds = layer_->bounds();
-  gfx::Rect src_subrect(bounds);
+  if (src_subrect.IsEmpty())
+    src_subrect = gfx::Rect(bounds);
   const gfx::Display& display =
       gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
   float device_scale_factor = display.device_scale_factor();
   DCHECK_GT(device_scale_factor, 0);
   gfx::Size dst_size(
       gfx::ToCeiledSize(gfx::ScaleSize(bounds, scale / device_scale_factor)));
   *out_size = dst_size;
   CopyFromCompositingSurface(
       src_subrect, dst_size, result_callback, SkBitmap::kARGB_8888_Config);
 }
@@ skipping 1223 matching lines @@
 // RenderWidgetHostView, public:
 
 // static
 RenderWidgetHostView*
 RenderWidgetHostView::CreateViewForWidget(RenderWidgetHost* widget) {
   RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(widget);
   return new RenderWidgetHostViewAndroid(rwhi, NULL);
 }
 
 } // namespace content