Enable SurfaceTexture based zero-copy texture uploading on Android platform

cc/resources/resource_provider.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/resources/resource_provider.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/containers/hash_tables.h"
@@ skipping 2132 matching lines @@
 
 uint8_t* ResourceProvider::MapImage(const Resource* resource, int* stride) {
   DCHECK(ReadLockFenceHasPassed(resource));
   DCHECK(resource->origin == Resource::Internal);
   DCHECK_EQ(resource->exported_count, 0);
 
   if (resource->type == GLTexture) {
     DCHECK(resource->image_id);
     GLES2Interface* gl = ContextGL();
     DCHECK(gl);
+    // For SurfaceTexture-backed GpuMemoryBuffer, the actual
+    // Stride can only be got after it is mapped and ANativeWindow_Buffer
+    // is locked.

[reveman, 2014/02/26 08:02:34]

We should probably make this a general requirement of the map-image extension
and make sure a DCHECK fails if used incorrectly on all platforms.

+    uint8_t* ret = static_cast<uint8_t*>(
+        gl->MapImageCHROMIUM(resource->image_id, GL_READ_WRITE));
     gl->GetImageParameterivCHROMIUM(
         resource->image_id, GL_IMAGE_ROWBYTES_CHROMIUM, stride);
-    return static_cast<uint8_t*>(
-        gl->MapImageCHROMIUM(resource->image_id, GL_READ_WRITE));
+    return ret;
   }
   DCHECK_EQ(Bitmap, resource->type);
   *stride = 0;
   return resource->pixels;
 }
 
 void ResourceProvider::UnmapImage(const Resource* resource) {
   DCHECK(resource->origin == Resource::Internal);
   DCHECK_EQ(resource->exported_count, 0);
 
@@ skipping 14 matching lines @@
   ContextProvider* context_provider = output_surface_->context_provider();
   return context_provider ? context_provider->ContextGL() : NULL;
 }
 
 class GrContext* ResourceProvider::GrContext() const {
   ContextProvider* context_provider = output_surface_->context_provider();
   return context_provider ? context_provider->GrContext() : NULL;
 }
 
 }  // namespace cc