Update GL_IMPLEMENTATION_COLOR_READ_FORMAT for BGRA

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 7a1628fc6b835178865826192bd7a0a85530230e..48e03942fe528fda810dc4f41ca3b981aa4ebc77 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -5106,14 +5106,17 @@ bool GLES2DecoderImpl::GetHelper(
     switch (pname) {
       case GL_IMPLEMENTATION_COLOR_READ_FORMAT:
         *num_written = 1;
-        // Return the GL implementation's preferred format and (see below type)
-        // if we have the GL extension that exposes this. This allows the GPU
-        // client to use the implementation's preferred format for glReadPixels
-        // for optimisation.
+        // Return an additional (other than GL_RGBA) read format which the GL
+        // implementation supports. If no additional format is available, this
+        // function will return GL_RGBA.
         //
-        // A conflicting extension (GL_ARB_ES2_compatibility) specifies an error
-        // case when requested on integer/floating point buffers but which is
-        // acceptable on GLES2 and with the GL_OES_read_format extension.
+        // If the GL_OES_read_format extension is available, we query GL
+        // directly. Otherwise we use our internal implementation.
+        //
+        // A conflicting extension (GL_ARB_ES2_compatibility) specifies an
+        // error case when requested on integer/floating point buffers but
+        // which is acceptable on GLES2 and with the GL_OES_read_format
+        // extension.
         //
         // Therefore if an error occurs we swallow the error and use the
         // internal implementation.
@@ -5125,8 +5128,9 @@ bool GLES2DecoderImpl::GetHelper(
             if (glGetError() == GL_NO_ERROR)
               return true;
           }
-          *params = GLES2Util::GetGLReadPixelsImplementationFormat(
-              GetBoundReadFrameBufferInternalFormat());
+          *params = GLES2Util::GetGLReadPixelsAdditionalFormat(
+              GetBoundReadFrameBufferInternalFormat(),
+              GetBoundReadFrameBufferTextureType());
         }
         return true;
       case GL_IMPLEMENTATION_COLOR_READ_TYPE:
@@ -5139,7 +5143,7 @@ bool GLES2DecoderImpl::GetHelper(
             if (glGetError() == GL_NO_ERROR)
               return true;
           }
-          *params = GLES2Util::GetGLReadPixelsImplementationType(
+          *params = GLES2Util::GetGLReadPixelsTypeForAdditionalFormat(
               GetBoundReadFrameBufferInternalFormat(),
               GetBoundReadFrameBufferTextureType());
         }