Reland of Extend CopyTextureCHROMIUM to more ES 3.0 texture formats.

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 d4292248285766b79cac5febb3d9f2cd8572fee6..5f070be19ec4e3579e995df49cafafcf63e0b882 100644
--- a/gpu/command_buffer/tests/gl_test_utils.h
+++ b/gpu/command_buffer/tests/gl_test_utils.h
@@ -64,7 +64,8 @@ class GLTestHelper {
                           GLsizei width,
                           GLsizei height,
                           GLint tolerance,
-                          const uint8_t* color);
+                          const uint8_t* color,
+                          int channel_count = 4);
 
   // Uses ReadPixels to save an area of the current FBO/Backbuffer.
   static bool SaveBackbufferAsBMP(const char* filename, int width, int height);