cc: Add threaded GPU rasterization.

Enable flag: --enable-threaded-gpu-rasterization

This patch enables threaded rasterization in GpuTileTaskWorkerPool.

There are some not yet landed/rolled dependencies:

  InProcessContextProvider Context Lost handling (jbauman@).
  Without this the feature should be considered unstable on WebViews.

BUG=454500

Review URL: https://codereview.chromium.org/916723002

Cr-Commit-Position: refs/heads/master@{#316333}

2 files changed, 5 insertions, 0 deletions

diff --git a/webkit/common/gpu/context_provider_in_process.cc b/webkit/common/gpu/context_provider_in_process.cc
index f2844b2..58bc7ec 100644
--- a/webkit/common/gpu/context_provider_in_process.cc
+++ b/webkit/common/gpu/context_provider_in_process.cc
@@ -109,6 +109,10 @@ bool ContextProviderInProcess::BindToCurrentThread() {
   return true;
 }
 
+void ContextProviderInProcess::DetachFromThread() {
+  context_thread_checker_.DetachFromThread();
+}
+
 void ContextProviderInProcess::InitializeCapabilities() {
   capabilities_.gpu = context3d_->GetImplementation()->capabilities();
 
diff --git a/webkit/common/gpu/context_provider_in_process.h b/webkit/common/gpu/context_provider_in_process.h
index b719d71..1bf376c 100644
--- a/webkit/common/gpu/context_provider_in_process.h
+++ b/webkit/common/gpu/context_provider_in_process.h
@@ -48,6 +48,7 @@ class WEBKIT_GPU_EXPORT ContextProviderInProcess
 
   // cc::ContextProvider:
   bool BindToCurrentThread() override;
+  void DetachFromThread() override;
   Capabilities ContextCapabilities() override;
   ::gpu::gles2::GLES2Interface* ContextGL() override;
   ::gpu::ContextSupport* ContextSupport() override;