Enable GL context virtualization for compositor contexts on Mac.

BUG=180463
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/13689003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193397 0039d316-1c4b-4281-b951-d872f2087c98

content/common/gpu/gpu_channel.cc

@@ -628,6 +628,14 @@ void GpuChannel::CreateViewCommandBuffer(
 
   GpuCommandBufferStub* share_group = stubs_.Lookup(init_params.share_group_id);
 
+  // Virtualize compositor contexts on OS X to prevent performance regressions
+  // when enabling FCM.
+  // http://crbug.com/180463
+  bool use_virtualized_gl_context = false;
+#if defined(OS_MACOSX)
+  use_virtualized_gl_context = true;
+#endif
+
   *route_id = GenerateRouteID();
   scoped_ptr<GpuCommandBufferStub> stub(new GpuCommandBufferStub(
       this,
@@ -640,6 +648,7 @@ void GpuChannel::CreateViewCommandBuffer(
       init_params.allowed_extensions,
       init_params.attribs,
       init_params.gpu_preference,
+      use_virtualized_gl_context,
       *route_id,
       surface_id,
       watchdog_,
@@ -857,8 +866,10 @@ void GpuChannel::OnCreateOffscreenCommandBuffer(
       init_params.allowed_extensions,
       init_params.attribs,
       init_params.gpu_preference,
+      false,
       *route_id,
-      0, watchdog_,
+      0,
+      watchdog_,
       software_,
       init_params.active_url));
   if (preempted_flag_.get())

content/common/gpu/gpu_command_buffer_stub.cc

@@ -107,6 +107,7 @@ GpuCommandBufferStub::GpuCommandBufferStub(
     const std::string& allowed_extensions,
     const std::vector<int32>& attribs,
     gfx::GpuPreference gpu_preference,
+    bool use_virtualized_gl_context,
     int32 route_id,
     int32 surface_id,
     GpuWatchdog* watchdog,
@@ -119,6 +120,7 @@ GpuCommandBufferStub::GpuCommandBufferStub(
       allowed_extensions_(allowed_extensions),
       requested_attribs_(attribs),
       gpu_preference_(gpu_preference),
+      use_virtualized_gl_context_(use_virtualized_gl_context),
       route_id_(route_id),
       surface_id_(surface_id),
       software_(software),
@@ -433,8 +435,9 @@ void GpuCommandBufferStub::OnInitialize(
   }
 
   scoped_refptr<gfx::GLContext> context;
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kEnableVirtualGLContexts) && channel_->share_group()) {
+  if ((CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableVirtualGLContexts) || use_virtualized_gl_context_) &&
+      channel_->share_group()) {
     context = channel_->share_group()->GetSharedContext();
     if (!context) {
       context = gfx::GLContext::CreateGLContext(

content/common/gpu/gpu_command_buffer_stub.h

@@ -69,6 +69,7 @@ class GpuCommandBufferStub
       const std::string& allowed_extensions,
       const std::vector<int32>& attribs,
       gfx::GpuPreference gpu_preference,
+      bool use_virtualized_gl_context,
       int32 route_id,
       int32 surface_id,
       GpuWatchdog* watchdog,
@@ -204,6 +205,7 @@ class GpuCommandBufferStub
   std::string allowed_extensions_;
   std::vector<int32> requested_attribs_;
   gfx::GpuPreference gpu_preference_;
+  bool use_virtualized_gl_context_;
   int32 route_id_;
   int32 surface_id_;
   bool software_;