aura: Allow in process ContextProvider to hold onscreen contexts.

webkit/common/gpu/context_provider_in_process.h

Index: webkit/common/gpu/context_provider_in_process.h
diff --git a/webkit/common/gpu/context_provider_in_process.h b/webkit/common/gpu/context_provider_in_process.h
index b427abeb043f6144adb281575c3af63e3218b2c7..169a1a8fdd3e6eab49eba6257e7c02199bd4904b 100644
--- a/webkit/common/gpu/context_provider_in_process.h
+++ b/webkit/common/gpu/context_provider_in_process.h
@@ -19,17 +19,21 @@ class WebGraphicsContext3D;
 namespace webkit {
 namespace gpu {
 class GrContextForWebGraphicsContext3D;
+class WebGraphicsContext3DInProcessCommandBufferImpl;
 
 class WEBKIT_GPU_EXPORT ContextProviderInProcess
     : NON_EXPORTED_BASE(public cc::ContextProvider) {
  public:
-  static scoped_refptr<ContextProviderInProcess> Create() {
-    scoped_refptr<ContextProviderInProcess> provider =
-        new ContextProviderInProcess;
-    if (!provider->InitializeOnMainThread())
-      return NULL;
-    return provider;
-  }
+  typedef base::Callback<
+      scoped_ptr<WebGraphicsContext3DInProcessCommandBufferImpl>(void)>
+      CreateCallback;
+
+  static scoped_refptr<ContextProviderInProcess> Create(
+      const CreateCallback& create_callback);
+
+  // Calls Create() with a default factory method for creating an offscreen
+  // context.
+  static scoped_refptr<ContextProviderInProcess> CreateOffscreen();
 
   virtual bool BindToCurrentThread() OVERRIDE;
   virtual WebKit::WebGraphicsContext3D* Context3d() OVERRIDE;
@@ -43,7 +47,8 @@ class WEBKIT_GPU_EXPORT ContextProviderInProcess
   ContextProviderInProcess();
   virtual ~ContextProviderInProcess();
 
-  bool InitializeOnMainThread();
+  bool InitializeOnMainThread(
+      const CreateCallback& create_callback);
 
   void OnLostContext();
   void OnMemoryAllocationChanged(bool nonzero_allocation);