Allow CopyFromBackingStore to fallback to copying from the renderer side if the accelerated surface…

content/browser/renderer_host/render_widget_host_impl.cc

Index: content/browser/renderer_host/render_widget_host_impl.cc
diff --git a/content/browser/renderer_host/render_widget_host_impl.cc b/content/browser/renderer_host/render_widget_host_impl.cc
index 2c9d0d2cb200ad954da2e802efaa9533c3f01721..ca5109618e13bf96c0c97e6c6f8a4283bc3f211e 100644
--- a/content/browser/renderer_host/render_widget_host_impl.cc
+++ b/content/browser/renderer_host/render_widget_host_impl.cc
@@ -391,6 +391,7 @@ bool RenderWidgetHostImpl::OnMessageReceived(const IPC::Message &msg) {
     IPC_MESSAGE_HANDLER(ViewHostMsg_WindowlessPluginDummyWindowDestroyed,
                         OnWindowlessPluginDummyWindowDestroyed)
 #endif
+    IPC_MESSAGE_HANDLER(ViewHostMsg_Snapshot, OnSnapshot)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP_EX()
 
@@ -573,9 +574,9 @@ void RenderWidgetHostImpl::CopyFromBackingStore(
   if (view_ && is_accelerated_compositing_active_) {
     TRACE_EVENT0("browser",
         "RenderWidgetHostImpl::CopyFromBackingStore::FromCompositingSurface");
-    gfx::Rect copy_rect = src_subrect.IsEmpty() ?
+    gfx::Rect accelerated_copy_rect = src_subrect.IsEmpty() ?
         gfx::Rect(view_->GetViewBounds().size()) : src_subrect;
-    view_->CopyFromCompositingSurface(copy_rect,
+    view_->CopyFromCompositingSurface(accelerated_copy_rect,
                                       accelerated_dst_size,
                                       callback);
     return;
@@ -598,6 +599,45 @@ void RenderWidgetHostImpl::CopyFromBackingStore(
   callback.Run(result, output.GetBitmap());
 }
 
+void RenderWidgetHostImpl::GetSnapshotFromRenderer(
+    const gfx::Rect& src_subrect,
+    const gfx::Size& dst_size,
+    const base::Callback<void(bool, const SkBitmap&)>& callback) {
+  TRACE_EVENT0("browser", "RenderWidgetHostImpl::GetSnapshotFromRenderer");
+  pending_snapshots_.push(std::make_pair(dst_size, callback));
+
+  gfx::Rect copy_rect = src_subrect.IsEmpty() ?
+      gfx::Rect(view_->GetViewBounds().size()) : src_subrect;
+  Send(new ViewMsg_Snapshot(routing_id_, copy_rect));
+}
+
+void RenderWidgetHostImpl::OnSnapshot(bool success,
+                                      const SkBitmap& bitmap) {
+  if (pending_snapshots_.size() == 0) {
+    LOG(ERROR) << "RenderWidgetHostImpl::OnSnapshot: "
+                  "Received a snapshot that was not requested.";
+    return;
+  }
+
+  PendingSnapshotInfo snapshot_info = pending_snapshots_.front();
+  pending_snapshots_.pop();
+
+  const gfx::Size& dst_size = snapshot_info.first;
+  const base::Callback<void(bool, const SkBitmap&)>& callback =
+      snapshot_info.second;
+
+  if (!success) {
+    callback.Run(success, SkBitmap());
+    return;
+  }
+
+  SkBitmap resized = skia::ImageOperations::Resize(
+      bitmap, skia::ImageOperations::RESIZE_GOOD, dst_size.width(),

[jamesr, 2013/03/18 22:41:18]

why RESIZE_GOOD? what did the old code use?

[justinlin, 2013/03/18 23:27:52]

The old code didn't really do the resize (CopyFromBackingStore in general only
does the resize in the accelerated path). I think it makes sense to just remove
it from this method. It's kind of janky to just use some arbitrary resize here
anyway; better let the caller figure it out.

+      dst_size.height());
+
+  callback.Run(success, resized);
+}
+
 #if defined(TOOLKIT_GTK)
 bool RenderWidgetHostImpl::CopyFromBackingStoreToGtkWindow(
     const gfx::Rect& dest_rect, GdkWindow* target) {