Use kRenderClientId command line flag when starting a render process

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 57bb2085f61e3f419307f96fb827956bc7ba7206..0e63da2205d974fcf9931ed6759234bbce4a1c7b 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -18,6 +18,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/stl_util.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_info.h"
 #include "base/trace_event/trace_event.h"
@@ -501,7 +502,6 @@ bool RenderWidget::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(ViewMsg_SetTextDirection, OnSetTextDirection)
     IPC_MESSAGE_HANDLER(ViewMsg_Move_ACK, OnRequestMoveAck)
     IPC_MESSAGE_HANDLER(ViewMsg_UpdateScreenRects, OnUpdateScreenRects)
-    IPC_MESSAGE_HANDLER(ViewMsg_SetFrameSinkId, OnSetFrameSinkId)
     IPC_MESSAGE_HANDLER(ViewMsg_WaitForNextFrameForTests,
                         OnWaitNextFrameForTests)
     IPC_MESSAGE_HANDLER(InputMsg_RequestCompositionUpdate,
@@ -1114,6 +1114,13 @@ void RenderWidget::initializeLayerTreeView() {
     compositor_->SetNeverVisible();
 
   StartCompositor();
+  DCHECK(base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kRendererClientId));
+  int32_t client_id;
+  base::StringToInt(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+                        switches::kRendererClientId),
+                    &client_id);
+  compositor_->SetFrameSinkId(cc::FrameSinkId(client_id, routing_id_));
 }
 
 void RenderWidget::WillCloseLayerTreeView() {
@@ -1508,11 +1515,6 @@ void RenderWidget::OnUpdateWindowScreenRect(
     window_screen_rect_ = window_screen_rect;
 }
 
-void RenderWidget::OnSetFrameSinkId(const cc::FrameSinkId& frame_sink_id) {
-  if (compositor_)
-    compositor_->SetFrameSinkId(frame_sink_id);
-}
-
 void RenderWidget::OnHandleCompositorProto(const std::vector<uint8_t>& proto) {
   if (compositor_)
     compositor_->OnHandleCompositorProto(proto);