Add RGB565 Texture readback support in gl_helper

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 6a9a341b24d9552fb9ec5d7c0893f7428d193015..1dd2083df51e6755c0abdf2e13b5aa6e9f4959da 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -589,7 +589,18 @@ void RenderWidgetHostViewAndroid::CopyFromCompositingSurface(
     callback.Run(false, SkBitmap());
     return;
   }
-
+  // Support format either  for ARGB8888 and RGB565.
+  bool readback_config_rgb565 = content_view_core_->IsReadBackConfig565();
+  ImageTransportFactoryAndroid* factory =
+      ImageTransportFactoryAndroid::GetInstance();
+  GLHelper* gl_helper = factory->GetGLHelper();
+  if (!gl_helper)
+    return;
+  if(readback_config_rgb565 && !gl_helper->CanUseRgb565Readback()){

[no sievers, 2014/01/07 16:26:02]

Can we check CanUseRgb565Readback() only once? It's not necessarily cheap
because it allocates memory and implies a synchronous GL call. Maybe a static
bool is good enough here.

[sivag, 2014/01/09 14:51:50]

Done.

+    LOG(ERROR) << "Readbackformat rgb565  not supported";
+    callback.Run(false, SkBitmap());
+    return;
+  }
   const gfx::Display& display =
       gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
   float device_scale_factor = display.device_scale_factor();
@@ -605,7 +616,6 @@ void RenderWidgetHostViewAndroid::CopyFromCompositingSurface(
     SynchronousCopyContents(src_subrect_in_pixel, dst_size_in_pixel, callback);
     return;
   }
-
   scoped_ptr<cc::CopyOutputRequest> request;
   if (src_subrect_in_pixel.size() == dst_size_in_pixel) {
       request = cc::CopyOutputRequest::CreateBitmapRequest(base::Bind(
@@ -616,6 +626,7 @@ void RenderWidgetHostViewAndroid::CopyFromCompositingSurface(
       request = cc::CopyOutputRequest::CreateRequest(base::Bind(
           &RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult,
           dst_size_in_pixel,
+          readback_config_rgb565,
           callback));
   }
   request->set_area(src_subrect_in_pixel);
@@ -1315,6 +1326,7 @@ void RenderWidgetHostViewAndroid::OnLostResources() {
 // static
 void RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult(
     const gfx::Size& dst_size_in_pixel,
+    bool readback_config_rgb565,
     const base::Callback<void(bool, const SkBitmap&)>& callback,
     scoped_ptr<cc::CopyOutputResult> result) {
   DCHECK(result->HasTexture());
@@ -1325,9 +1337,16 @@ void RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult(
     return;
 
   scoped_ptr<SkBitmap> bitmap(new SkBitmap);
-  bitmap->setConfig(SkBitmap::kARGB_8888_Config,
+  if(readback_config_rgb565){
+     bitmap->setConfig(SkBitmap::kRGB_565_Config,

[no sievers, 2014/01/07 16:26:02]

nit: no need for if-else, can do 'readback_config_rgb565 ? : ... : ...'

[sivag, 2014/01/09 14:51:50]

Done.

                     dst_size_in_pixel.width(), dst_size_in_pixel.height(),
                     0, kOpaque_SkAlphaType);
+  }
+  else{
+     bitmap->setConfig(SkBitmap::kARGB_8888_Config,
+                    dst_size_in_pixel.width(), dst_size_in_pixel.height(),

[no sievers, 2014/01/07 16:26:02]

nit: indent here and above

[sivag, 2014/01/09 14:51:50]

Done.

+                    0, kOpaque_SkAlphaType);
+  }
   if (!bitmap->allocPixels())
     return;
 
@@ -1357,6 +1376,7 @@ void RenderWidgetHostViewAndroid::PrepareTextureCopyOutputResult(
       gfx::Rect(result->size()),
       dst_size_in_pixel,
       pixels,
+      readback_config_rgb565,
       base::Bind(&CopyFromCompositingSurfaceFinished,
                  callback,
                  base::Passed(&release_callback),