Add a workaround for copyTexImage2D as it is sometimes broken on OSX.

gpu/command_buffer/tests/gl_test_utils.h

Index: gpu/command_buffer/tests/gl_test_utils.h
diff --git a/gpu/command_buffer/tests/gl_test_utils.h b/gpu/command_buffer/tests/gl_test_utils.h
index 537442fbe035eab42f454ff21ceff002b00ff875..e2f88f5c2022b0d70c8e40b4638401af7f7c8c60 100644
--- a/gpu/command_buffer/tests/gl_test_utils.h
+++ b/gpu/command_buffer/tests/gl_test_utils.h
@@ -10,6 +10,10 @@
 #include <GLES2/gl2.h>
 #include <stdint.h>
 
+namespace gfx {
+class Size;
+}  // namespace gfx
+
 class GLTestHelper {
  public:
   static const uint8_t kCheckClearValue = 123u;
@@ -58,6 +62,8 @@ class GLTestHelper {
 
   // Uses ReadPixels to save an area of the current FBO/Backbuffer.
   static bool SaveBackbufferAsBMP(const char* filename, int width, int height);
+
+  static void DrawTextureQuad(GLenum target, const gfx::Size& size);
 };
 
 #endif  // GPU_COMMAND_BUFFER_TESTS_GL_TEST_UTILS_H_