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

content/browser/renderer_host/render_widget_host_impl.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_impl.h"
 
 #include <math.h>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 373 matching lines @@
     IPC_MESSAGE_HANDLER(ViewHostMsg_LockMouse, OnLockMouse)
     IPC_MESSAGE_HANDLER(ViewHostMsg_UnlockMouse, OnUnlockMouse)
     IPC_MESSAGE_HANDLER(ViewHostMsg_ShowDisambiguationPopup,
                         OnShowDisambiguationPopup)
 #if defined(OS_WIN)
     IPC_MESSAGE_HANDLER(ViewHostMsg_WindowlessPluginDummyWindowCreated,
                         OnWindowlessPluginDummyWindowCreated)
     IPC_MESSAGE_HANDLER(ViewHostMsg_WindowlessPluginDummyWindowDestroyed,
                         OnWindowlessPluginDummyWindowDestroyed)
 #endif
+    IPC_MESSAGE_HANDLER(ViewHostMsg_Snapshot, OnSnapshot)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP_EX()
 
   if (!handled && view_ && view_->OnMessageReceived(msg))
     return true;
 
   if (!msg_is_ok) {
     // The message de-serialization failed. Kill the renderer process.
     RecordAction(UserMetricsAction("BadMessageTerminate_RWH"));
     GetProcess()->ReceivedBadMessage();
@@ skipping 162 matching lines @@
   view_->SetIsLoading(is_loading);
 }
 
 void RenderWidgetHostImpl::CopyFromBackingStore(
     const gfx::Rect& src_subrect,
     const gfx::Size& accelerated_dst_size,
     const base::Callback<void(bool, const SkBitmap&)>& callback) {
   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;
   }
 
   BackingStore* backing_store = GetBackingStore(false);
   if (!backing_store) {
     callback.Run(false, SkBitmap());
     return;
   }
 
   TRACE_EVENT0("browser",
       "RenderWidgetHostImpl::CopyFromBackingStore::FromBackingStore");
   gfx::Rect copy_rect = src_subrect.IsEmpty() ?
       gfx::Rect(backing_store->size()) : src_subrect;
   // When the result size is equal to the backing store size, copy from the
   // backing store directly to the output canvas.
   skia::PlatformBitmap output;
   bool result = backing_store->CopyFromBackingStore(copy_rect, &output);
   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) {
   BackingStore* backing_store = GetBackingStore(false);
   if (!backing_store)
     return false;
   (static_cast<BackingStoreGtk*>(backing_store))->PaintToRect(
       dest_rect, target);
   return true;
 }
@@ skipping 1799 matching lines @@
     return;
 
   OnRenderAutoResized(new_size);
 }
 
 void RenderWidgetHostImpl::DetachDelegate() {
   delegate_ = NULL;
 }
 
 }  // namespace content