aura: Remove CreateOffscreenContext from ui::ContextFactory.

ui/aura/bench/bench_main.cc

Index: ui/aura/bench/bench_main.cc
diff --git a/ui/aura/bench/bench_main.cc b/ui/aura/bench/bench_main.cc
index aee7e79c83a417a9ffbc5865163e438e4fdd4e5f..17ed068e60b97ed9c31cdd9bcb970c68ac08adc5 100644
--- a/ui/aura/bench/bench_main.cc
+++ b/ui/aura/bench/bench_main.cc
@@ -10,6 +10,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_split.h"
 #include "base/time/time.h"
+#include "cc/output/context_provider.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "third_party/skia/include/core/SkXfermode.h"
 #include "ui/aura/client/default_capture_client.h"
@@ -181,7 +182,7 @@ class WebGLBench : public BenchCompositorObserver {
         parent_(parent),
         webgl_(ui::LAYER_TEXTURED),
         compositor_(compositor),
-        context_(),
+        context_provider_(),
         texture_(),
         fbo_(0),
         do_draw_(true) {
@@ -207,24 +208,26 @@ class WebGLBench : public BenchCompositorObserver {
     webgl_.SetBounds(bounds);
     parent_->Add(&webgl_);
 
-    context_ = ui::ContextFactory::GetInstance()->CreateOffscreenContext();
-    context_->makeContextCurrent();
-    texture_ = new WebGLTexture(context_.get(), bounds.size());
-    fbo_ = context_->createFramebuffer();
+    context_provider_ = ui::ContextFactory::GetInstance()
+        ->OffscreenContextProviderForMainThread();
+    WebKit::WebGraphicsContext3D* context = context_provider_->Context3d();
+    context->makeContextCurrent();
+    texture_ = new WebGLTexture(context, bounds.size());
+    fbo_ = context->createFramebuffer();
     compositor->AddObserver(this);
     webgl_.SetExternalTexture(texture_.get());
-    context_->bindFramebuffer(GL_FRAMEBUFFER, fbo_);
-    context_->framebufferTexture2D(
+    context->bindFramebuffer(GL_FRAMEBUFFER, fbo_);
+    context->framebufferTexture2D(
         GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
         GL_TEXTURE_2D, texture_->PrepareTexture(), 0);
-    context_->clearColor(0.f, 1.f, 0.f, 1.f);
-    context_->clear(GL_COLOR_BUFFER_BIT);
-    context_->flush();
+    context->clearColor(0.f, 1.f, 0.f, 1.f);
+    context->clear(GL_COLOR_BUFFER_BIT);
+    context->flush();
   }
 
   virtual ~WebGLBench() {
-    context_->makeContextCurrent();
-    context_->deleteFramebuffer(fbo_);
+    context_provider_->Context3d()->makeContextCurrent();
+    context_provider_->Context3d()->deleteFramebuffer(fbo_);
     webgl_.SetExternalTexture(NULL);
     texture_ = NULL;
     compositor_->RemoveObserver(this);
@@ -232,10 +235,11 @@ class WebGLBench : public BenchCompositorObserver {
 
   virtual void Draw() OVERRIDE {
     if (do_draw_) {
-      context_->makeContextCurrent();
-      context_->clearColor((frames() % kFrames)*1.0/kFrames, 1.f, 0.f, 1.f);
-      context_->clear(GL_COLOR_BUFFER_BIT);
-      context_->flush();
+      WebKit::WebGraphicsContext3D* context = context_provider_->Context3d();
+      context->makeContextCurrent();
+      context->clearColor((frames() % kFrames)*1.0/kFrames, 1.f, 0.f, 1.f);
+      context->clear(GL_COLOR_BUFFER_BIT);
+      context->flush();
     }
     webgl_.SetExternalTexture(texture_.get());
     webgl_.SchedulePaint(gfx::Rect(webgl_.bounds().size()));
@@ -246,7 +250,7 @@ class WebGLBench : public BenchCompositorObserver {
   Layer* parent_;
   Layer webgl_;
   Compositor* compositor_;
-  scoped_ptr<WebGraphicsContext3D> context_;
+  scoped_refptr<cc::ContextProvider> context_provider_;
   scoped_refptr<WebGLTexture> texture_;
 
   // The FBO that is used to render to the texture.