Adding a new IPC message to notify the browser process when a render widget is using the gpu process for painting its contents so that the browser will stop rendering from its own backing surface. This will currently only trigger if a page

uses the accelerated compositing path.
This patch can only land _after_ https://bugs.webkit.org/show_bug.cgi?id=38220

BUG=42677
TEST=NONE
Review URL: http://codereview.chromium.org/1696014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@46697 0039d316-1c4b-4281-b951-d872f2087c98

6 files changed, 50 insertions, 1 deletions

diff --git a/chrome/browser/renderer_host/render_widget_host.cc b/chrome/browser/renderer_host/render_widget_host.cc
index 6c77f07..c53c7be 100644
--- a/chrome/browser/renderer_host/render_widget_host.cc
+++ b/chrome/browser/renderer_host/render_widget_host.cc
@@ -64,6 +64,7 @@ RenderWidgetHost::RenderWidgetHost(RenderProcessHost* process,
       routing_id_(routing_id),
       is_loading_(false),
       is_hidden_(false),
+      is_gpu_rendering_active_(false),
       repaint_ack_pending_(false),
       resize_ack_pending_(false),
       mouse_move_pending_(false),
@@ -138,6 +139,8 @@ void RenderWidgetHost::OnMessageReceived(const IPC::Message &msg) {
     IPC_MESSAGE_HANDLER(ViewHostMsg_FocusedNodeChanged, OnMsgFocusedNodeChanged)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SetCursor, OnMsgSetCursor)
     IPC_MESSAGE_HANDLER(ViewHostMsg_ImeUpdateStatus, OnMsgImeUpdateStatus)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_GpuRenderingActivated,
+                        OnMsgGpuRenderingActivated)
 #if defined(OS_LINUX)
     IPC_MESSAGE_HANDLER(ViewHostMsg_CreatePluginContainer,
                         OnMsgCreatePluginContainer)
@@ -881,6 +884,10 @@ void RenderWidgetHost::OnMsgImeUpdateStatus(int control,
   }
 }
 
+void RenderWidgetHost::OnMsgGpuRenderingActivated(bool activated) {
+  is_gpu_rendering_active_ = activated;
+}
+
 #if defined(OS_LINUX)
 
 void RenderWidgetHost::OnMsgCreatePluginContainer(gfx::PluginWindowHandle id) {
diff --git a/chrome/browser/renderer_host/render_widget_host.h b/chrome/browser/renderer_host/render_widget_host.h
index 7b87d13..4e5c903 100644
--- a/chrome/browser/renderer_host/render_widget_host.h
+++ b/chrome/browser/renderer_host/render_widget_host.h
@@ -199,6 +199,9 @@ class RenderWidgetHost : public IPC::Channel::Listener,
   void Blur();
   void LostCapture();
 
+  // Tells us whether the page is rendered directly via the GPU process.
+  bool is_gpu_rendering_active() { return is_gpu_rendering_active_; }
+
   // Notifies the RenderWidgetHost that the View was destroyed.
   void ViewDestroyed();
 
@@ -458,6 +461,8 @@ class RenderWidgetHost : public IPC::Channel::Listener,
   // having to bring in render_messages.h in a header file.
   void OnMsgImeUpdateStatus(int control, const gfx::Rect& caret_rect);
 
+  void OnMsgGpuRenderingActivated(bool activated);
+
 #if defined(OS_LINUX)
   void OnMsgCreatePluginContainer(gfx::PluginWindowHandle id);
   void OnMsgDestroyPluginContainer(gfx::PluginWindowHandle id);
@@ -535,6 +540,9 @@ class RenderWidgetHost : public IPC::Channel::Listener,
   // Indicates whether a page is hidden or not.
   bool is_hidden_;
 
+  // True when a page is rendered directly via the GPU process.
+  bool is_gpu_rendering_active_;
+
   // Set if we are waiting for a repaint ack for the view.
   bool repaint_ack_pending_;
 
diff --git a/chrome/browser/renderer_host/render_widget_host_view_win.cc b/chrome/browser/renderer_host/render_widget_host_view_win.cc
index 975609e..3fede8e 100644
--- a/chrome/browser/renderer_host/render_widget_host_view_win.cc
+++ b/chrome/browser/renderer_host/render_widget_host_view_win.cc
@@ -871,6 +871,16 @@ void RenderWidgetHostViewWin::OnPaint(HDC unused_dc) {
     return;
   }
 
+  // Don't do any painting if the GPU process is rendering directly
+  // into the View.
+  RenderWidgetHost* render_widget_host = GetRenderWidgetHost();
+  if (render_widget_host->is_gpu_rendering_active()) {
+    // We initialize paint_dc here so that BeginPaint()/EndPaint()
+    // get called to validate the region.
+    CPaintDC paint_dc(m_hWnd);
+    return;
+  }
+
   about_to_validate_and_paint_ = true;
   BackingStoreWin* backing_store = static_cast<BackingStoreWin*>(
       render_widget_host_->GetBackingStore(true));
diff --git a/chrome/common/render_messages_internal.h b/chrome/common/render_messages_internal.h
index 85ce45f..763715a 100644
--- a/chrome/common/render_messages_internal.h
+++ b/chrome/common/render_messages_internal.h
@@ -1115,6 +1115,11 @@ IPC_BEGIN_MESSAGES(ViewHost)
                       gfx::Rect /* bitmap_rect */)
   IPC_MESSAGE_ROUTED0(ViewHostMsg_DestroyVideo)
 
+  // Sent by the renderer when GPU compositing is enabled or disabled to notify
+  // the browser whether or not is should do paiting.
+  IPC_MESSAGE_ROUTED1(ViewHostMsg_GpuRenderingActivated,
+                      bool /* true if the GPU process renders to window */)
+
   // Acknowledges receipt of a ViewMsg_HandleInputEvent message.
   // Payload is a WebInputEvent::Type which is the type of the event, followed
   // by an optional WebInputEvent which is provided only if the event was not
diff --git a/chrome/renderer/render_widget.cc b/chrome/renderer/render_widget.cc
index 7952982..d9fd8e7 100644
--- a/chrome/renderer/render_widget.cc
+++ b/chrome/renderer/render_widget.cc
@@ -70,7 +70,8 @@ RenderWidget::RenderWidget(RenderThreadBase* render_thread,
       ime_control_busy_(false),
       popup_type_(popup_type),
       pending_window_rect_count_(0),
-      suppress_next_char_events_(false) {
+      suppress_next_char_events_(false),
+      is_gpu_rendering_active_(false) {
   RenderProcess::current()->AddRefProcess();
   DCHECK(render_thread_);
 }
@@ -440,6 +441,21 @@ void RenderWidget::DoDeferredUpdate() {
     return;
   }
 
+  // If we are using accelerated compositing then all the drawing
+  // to the associated window happens directly from the gpu process and the
+  // browser process shouldn't do any drawing.
+  // TODO(vangelis): Currently the accelerated compositing path relies on
+  // invalidating parts of the page so that we get a request to redraw.
+  // This needs to change to a model where the compositor updates the
+  // contents of the page independently and the browser process gets no
+  // longer involved.
+  if (webwidget_->isAcceleratedCompositingActive() !=
+      is_gpu_rendering_active_) {
+    is_gpu_rendering_active_ = webwidget_->isAcceleratedCompositingActive();
+    Send(new ViewHostMsg_GpuRenderingActivated(
+        routing_id_, is_gpu_rendering_active_));
+  }
+
   // Layout may generate more invalidation.
   webwidget_->layout();
 
diff --git a/chrome/renderer/render_widget.h b/chrome/renderer/render_widget.h
index 9577630..4232d28 100644
--- a/chrome/renderer/render_widget.h
+++ b/chrome/renderer/render_widget.h
@@ -325,6 +325,9 @@ class RenderWidget : public IPC::Channel::Listener,
   // Indicates if the next sequence of Char events should be suppressed or not.
   bool suppress_next_char_events_;
 
+  // Set to true if painting to the window is handled by the GPU process.
+  bool is_gpu_rendering_active_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };