Enable SurfaceTexture based zero-copy texture uploading on Android platform

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 e58ed0b73b7c33c01b62ae654d8ec3bdf1664704..e1e66fafbb1a5ec6cc140bfd6fd7f89d6528336d 100644
--- a/cc/resources/resource_provider.cc
+++ b/cc/resources/resource_provider.cc
@@ -2150,10 +2150,14 @@ uint8_t* ResourceProvider::MapImage(const Resource* resource, int* stride) {
     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;