mac: Fix an error in a unit_test from linking against the 10.10 SDK.

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 602d2615f7291fd67118b1cd940dabe38546737f..29a21d0881c30eb28393eca4a11774977977d632 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -5986,7 +5986,11 @@ bool GLES2DecoderImpl::VerifyMultisampleRenderbufferIntegrity(
 
     // Texture only needs to be 1x1.
     glBindTexture(GL_TEXTURE_2D, validation_texture_);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 1, 1, 0, GL_RGB,
+    // TODO(erikchen): When Chrome on Mac is linked against an OSX 10.9+ SDK, a
+    // multisample will fail if the color format of the source and destination
+    // do not match. Here, we assume that the source is GL_RGBA, and make the
+    // destination GL_RGBA. http://crbug.com/484203
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA,
         GL_UNSIGNED_BYTE, NULL);
 
     glBindFramebufferEXT(GL_FRAMEBUFFER, validation_fbo_);