(not for commit) Simplified multi-threaded Ganesh with lock on Flush only.

cc/resources/resource_provider.cc

Index: cc/resources/resource_provider.cc
diff --git a/cc/resources/resource_provider.cc b/cc/resources/resource_provider.cc
index b90b59477376960656266cdb0f60b87d0d8173b0..2856a6ecdb6e6b6e31a3686439a79b74f1ae80cd 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -430,15 +430,13 @@ scoped_ptr<ResourceProvider> ResourceProvider::Create(
     BlockingTaskRunner* blocking_main_thread_task_runner,
     int highp_threshold_min,
     bool use_rgba_4444_texture_format,
+    bool use_worker_context_for_gr,
     size_t id_allocation_chunk_size) {
-  scoped_ptr<ResourceProvider> resource_provider(
-      new ResourceProvider(output_surface,
-                           shared_bitmap_manager,
-                           gpu_memory_buffer_manager,
-                           blocking_main_thread_task_runner,
-                           highp_threshold_min,
-                           use_rgba_4444_texture_format,
-                           id_allocation_chunk_size));
+  scoped_ptr<ResourceProvider> resource_provider(new ResourceProvider(
+      output_surface, shared_bitmap_manager, gpu_memory_buffer_manager,
+      blocking_main_thread_task_runner, highp_threshold_min,
+      use_rgba_4444_texture_format, use_worker_context_for_gr,
+      id_allocation_chunk_size));
 
   if (resource_provider->ContextGL())
     resource_provider->InitializeGL();
@@ -1087,17 +1085,25 @@ ResourceProvider::ScopedWriteLockGpuMemoryBuffer::GetGpuMemoryBuffer() {
 
 ResourceProvider::ScopedWriteLockGr::ScopedWriteLockGr(
     ResourceProvider* resource_provider,
-    ResourceProvider::ResourceId resource_id,
-    bool use_distance_field_text,
-    bool can_use_lcd_text,
-    int msaa_sample_count)
+    ResourceProvider::ResourceId resource_id)
     : resource_provider_(resource_provider),
       resource_(resource_provider->LockForWrite(resource_id)) {
-  // Create the sk_surface.
+  resource_provider_->LazyAllocate(resource_);
+}
+
+ResourceProvider::ScopedWriteLockGr::~ScopedWriteLockGr() {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(resource_->locked_for_write);
+  resource_provider_->UnlockForWrite(resource_);
+}
 
-  resource_provider_->LazyAllocate(resource_);
+SkSurface* ResourceProvider::ScopedWriteLockGr::GetSkSurface(
+    bool use_distance_field_text,
+    bool can_use_lcd_text,
+    int msaa_sample_count) {
+  // TODO(vmiura): Update DCHECK later to match worker thread.
+  // DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(resource_->locked_for_write);
 
   GrBackendTextureDesc desc;
   desc.fFlags = kRenderTarget_GrBackendTextureFlag;
@@ -1122,14 +1128,14 @@ ResourceProvider::ScopedWriteLockGr::ScopedWriteLockGr(
       surface_props =
           SkSurfaceProps(flags, SkSurfaceProps::kLegacyFontHost_InitType);
     }
-    sk_surface_ = skia::AdoptRef(SkSurface::NewRenderTargetDirect(
-        gr_texture->asRenderTarget(), &surface_props));
+    // TODO(vmiura): I removed this reference so that we don't delete it on the
+    // compositor thread later.  For now, releasing it on the worker thread.
+    // resource_->sk_surface = skia::AdoptRef(SkSurface::NewRenderTargetDirect(
+    //    gr_texture->asRenderTarget(), &surface_props));
+    return SkSurface::NewRenderTargetDirect(gr_texture->asRenderTarget(),
+                                            &surface_props);
   }
-}
-
-ResourceProvider::ScopedWriteLockGr::~ScopedWriteLockGr() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  resource_provider_->UnlockForWrite(resource_);
+  return nullptr;
 }
 
 ResourceProvider::SynchronousFence::SynchronousFence(
@@ -1168,6 +1174,7 @@ ResourceProvider::ResourceProvider(
     BlockingTaskRunner* blocking_main_thread_task_runner,
     int highp_threshold_min,
     bool use_rgba_4444_texture_format,
+    bool use_worker_context_for_gr,
     size_t id_allocation_chunk_size)
     : output_surface_(output_surface),
       shared_bitmap_manager_(shared_bitmap_manager),
@@ -1186,6 +1193,7 @@ ResourceProvider::ResourceProvider(
       max_texture_size_(0),
       best_texture_format_(RGBA_8888),
       use_rgba_4444_texture_format_(use_rgba_4444_texture_format),
+      use_worker_context_for_gr_(use_worker_context_for_gr),
       id_allocation_chunk_size_(id_allocation_chunk_size),
       use_sync_query_(false) {
   DCHECK(output_surface_->HasClient());
@@ -2136,7 +2144,9 @@ GLES2Interface* ResourceProvider::ContextGL() const {
 }
 
 class GrContext* ResourceProvider::GrContext() const {
-  ContextProvider* context_provider = output_surface_->context_provider();
+  ContextProvider* context_provider =
+      use_worker_context_for_gr_ ? output_surface_->worker_context_provider()
+                                 : output_surface_->context_provider();
   return context_provider ? context_provider->GrContext() : NULL;
 }