Query the preferred readback config in CopyFromBackingStore

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/android/sys_utils.h"
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/worker_pool.h"
 #include "cc/base/latency_info_swap_promise.h"
@@ skipping 1360 matching lines @@
 bool RenderWidgetHostViewAndroid::IsReadbackConfigSupported(
     SkBitmap::Config bitmap_config) {
   ImageTransportFactoryAndroid* factory =
       ImageTransportFactoryAndroid::GetInstance();
   GLHelper* gl_helper = factory->GetGLHelper();
   if (!gl_helper)
     return false;
   return gl_helper->IsReadbackConfigSupported(bitmap_config);
 }
 
+SkBitmap::Config RenderWidgetHostViewAndroid::PreferredReadbackFormat() {
+  // Define the criteria here. If say the 16 texture readback is
+  // supported we should go with that (this degrades quality)
+  // or stick back to the default format.
+  if (base::android::SysUtils::IsLowEndDevice()) {
+    if (IsReadbackConfigSupported(SkBitmap::kRGB_565_Config))
+      return SkBitmap::kRGB_565_Config;
+  }
+  return SkBitmap::kARGB_8888_Config;
+}
+
 // static
 void RenderWidgetHostViewPort::GetDefaultScreenInfo(
     blink::WebScreenInfo* results) {
   const gfx::Display& display =
       gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
   results->rect = display.bounds();
   // TODO(husky): Remove any system controls from availableRect.
   results->availableRect = display.work_area();
   results->deviceScaleFactor = display.device_scale_factor();
   gfx::DeviceDisplayInfo info;
   results->depth = info.GetBitsPerPixel();
   results->depthPerComponent = info.GetBitsPerComponent();
   results->isMonochrome = (results->depthPerComponent == 0);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostView, public:
 
 // static
 RenderWidgetHostView*
 RenderWidgetHostView::CreateViewForWidget(RenderWidgetHost* widget) {
   RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(widget);
   return new RenderWidgetHostViewAndroid(rwhi, NULL);
 }
 
 } // namespace content