[Android] Implement asynchronous zero-copy bitmap capture API.

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 16e367f02c2a92117c27160011fc4630ff6d6c8c..b0fd37f286625699bde6302a2dc2eca9f9fbeee2 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -253,13 +253,18 @@ void RenderWidgetHostViewAndroid::SetBounds(const gfx::Rect& rect) {
 
 void RenderWidgetHostViewAndroid::GetScaledContentBitmap(
     float scale,
-    const base::Callback<void(bool, const SkBitmap&)>& result_callback) {
+    const base::Callback<void(bool, const SkBitmap&)>& result_callback,
+    SkBitmap::Config bitmap_config,
+    const gfx::Rect& bounding_rect,
+    const BitmapAllocator bitmap_allocator) {
   if (!IsSurfaceAvailableForCopy()) {
     result_callback.Run(false, SkBitmap());
     return;
   }
 
-  gfx::Size bounds = layer_->bounds();
+  gfx::Size bounds = bounding_rect.IsEmpty() ?
+                     layer_->bounds() :
+                     gfx::Size(bounding_rect.width(), bounding_rect.height());
   gfx::Rect src_subrect(bounds);
   const gfx::Display& display =
       gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
@@ -267,8 +272,21 @@ void RenderWidgetHostViewAndroid::GetScaledContentBitmap(
   DCHECK_GT(device_scale_factor, 0);
   gfx::Size dst_size(
       gfx::ToCeiledSize(gfx::ScaleSize(bounds, scale / device_scale_factor)));
+
+  scoped_ptr<SkBitmap> bitmap;
+  if (!bitmap_allocator.is_null()) {
+    SkBitmap* bitmap_ptr = NULL;
+    bitmap_allocator.Run(bitmap_ptr, dst_size, bitmap_config);
+    DCHECK(bitmap_ptr);
+    DCHECK_EQ(bitmap_ptr->width(), bounds.width());
+    DCHECK_EQ(bitmap_ptr->height(), bounds.height());
+    DCHECK_EQ(bitmap_ptr->config(), bitmap_config);
+    DCHECK_NE(bitmap_ptr->getPixels(), static_cast<void*>(NULL));
+    bitmap.reset(bitmap_ptr);
+  }
+
   CopyFromCompositingSurface(
-      src_subrect, dst_size, result_callback, SkBitmap::kARGB_8888_Config);
+      src_subrect, dst_size, result_callback, bitmap_config, bitmap.Pass());
 }
 
 bool RenderWidgetHostViewAndroid::PopulateBitmapWithContents(jobject jbitmap) {
@@ -621,7 +639,8 @@ void RenderWidgetHostViewAndroid::CopyFromCompositingSurface(
     const gfx::Rect& src_subrect,
     const gfx::Size& dst_size,
     const base::Callback<void(bool, const SkBitmap&)>& callback,
-    const SkBitmap::Config bitmap_config) {
+    const SkBitmap::Config bitmap_config,
+    scoped_ptr<SkBitmap> bitmap) {
   // Only ARGB888 and RGB565 supported as of now.
   bool format_support = ((bitmap_config == SkBitmap::kRGB_565_Config) ||
                          (bitmap_config == SkBitmap::kARGB_8888_Config));
@@ -668,6 +687,7 @@ void RenderWidgetHostViewAndroid::CopyFromCompositingSurface(
           dst_size_in_pixel,
           bitmap_config,
           start_time,
+          base::Passed(&bitmap),
           callback));
   request->set_area(src_subrect_in_pixel);
   layer_->RequestCopyOfOutput(request.Pass());
@@ -1335,6 +1355,7 @@ void RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult(
     const gfx::Size& dst_size_in_pixel,
     const SkBitmap::Config bitmap_config,
     const base::TimeTicks& start_time,
+    scoped_ptr<SkBitmap> bitmap,
     const base::Callback<void(bool, const SkBitmap&)>& callback,
     scoped_ptr<cc::CopyOutputResult> result) {
   base::ScopedClosureRunner scoped_callback_runner(
@@ -1343,13 +1364,15 @@ void RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult(
   if (!result->HasTexture() || result->IsEmpty() || result->size().IsEmpty())
     return;
 
-  scoped_ptr<SkBitmap> bitmap(new SkBitmap);
-  bitmap->setConfig(bitmap_config,
-                    dst_size_in_pixel.width(),
-                    dst_size_in_pixel.height(),
-                    0, kOpaque_SkAlphaType);
-  if (!bitmap->allocPixels())
-    return;
+  if (!bitmap.get()) {
+    bitmap.reset(new SkBitmap);
+    bitmap->setConfig(bitmap_config,
+                      dst_size_in_pixel.width(),
+                      dst_size_in_pixel.height(),
+                      0, kOpaque_SkAlphaType);
+    if (!bitmap->allocPixels())
+      return;
+  }
 
   ImageTransportFactoryAndroid* factory =
       ImageTransportFactoryAndroid::GetInstance();