Adds support for the GL_ANGLE_texture_usage and GL_EXT_texture_storage

content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h

Index: content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h
===================================================================
--- content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h	(revision 112643)
+++ content/renderer/gpu/webgraphicscontext3d_command_buffer_impl.h	(working copy)
@@ -461,6 +461,10 @@
       WGC3Denum target, WGC3Dint width, WGC3Dint height,
       WGC3Duint ioSurfaceId, WGC3Duint plane);
 
+  virtual void texStorage2DEXT(
+      WGC3Denum target, WGC3Dint levels, WGC3Duint internalformat,
+      WGC3Dint width, WGC3Dint height);
+
  protected:
 #if WEBKIT_USING_SKIA
   virtual GrGLInterface* onCreateGrGLInterface();