Update from https://crrev.com/312398

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 6409 matching lines @@
         TextureUnit& texture_unit = state_.texture_units[texture_unit_index];
         TextureRef* texture_ref =
             texture_unit.GetInfoForSamplerType(uniform_info->type).get();
         GLenum textarget = GetBindTargetForSamplerType(uniform_info->type);
         if (!texture_ref || !texture_manager()->CanRender(texture_ref)) {
           textures_set = true;
           glActiveTexture(GL_TEXTURE0 + texture_unit_index);
           glBindTexture(
               textarget,
               texture_manager()->black_texture_id(uniform_info->type));
-          LOCAL_RENDER_WARNING(
-              std::string("texture bound to texture unit ") +
-              base::IntToString(texture_unit_index) +
-              " is not renderable. It maybe non-power-of-2 and have"
-              " incompatible texture filtering or is not"
-              " 'texture complete'");
+          if (!texture_ref) {
+            LOCAL_RENDER_WARNING(
+                std::string("there is no texture bound to the unit ") +
+                base::IntToString(texture_unit_index));
+          } else {
+            LOCAL_RENDER_WARNING(
+                std::string("texture bound to texture unit ") +
+                base::IntToString(texture_unit_index) +
+                " is not renderable. It maybe non-power-of-2 and have"
+                " incompatible texture filtering.");
+          }
           continue;
         }
 
         if (textarget != GL_TEXTURE_CUBE_MAP) {
           Texture* texture = texture_ref->texture();
           gfx::GLImage* image = texture->GetLevelImage(textarget, 0);
           if (image && !texture->IsAttachedToFramebuffer()) {
             ScopedGLErrorSuppressor suppressor(
                 "GLES2DecoderImpl::PrepareTexturesForRender", GetErrorState());
             textures_set = true;
@@ skipping 2687 matching lines @@
 
   ScopedResolvedFrameBufferBinder binder(this, false, true);
   gfx::Size size = GetBoundReadFrameBufferSize();
   GLint copyX = 0;
   GLint copyY = 0;
   GLint copyWidth = 0;
   GLint copyHeight = 0;
   Clip(x, width, size.width(), &copyX, &copyWidth);
   Clip(y, height, size.height(), &copyY, &copyHeight);
 
-  if (!texture_manager()->ClearTextureLevel(this, texture_ref, target, level)) {
-    LOCAL_SET_GL_ERROR(
-        GL_OUT_OF_MEMORY, "glCopyTexSubImage2D", "dimensions too big");
-    return;
+  if (xoffset != 0 || yoffset != 0 || width != size.width() ||
+      height != size.height()) {
+    if (!texture_manager()->ClearTextureLevel(this, texture_ref, target,
+                                              level)) {
+      LOCAL_SET_GL_ERROR(GL_OUT_OF_MEMORY, "glCopyTexSubImage2D",
+                         "dimensions too big");
+      return;
+    }
+  } else {
+    // Write all pixels in below.
+    texture_manager()->SetLevelCleared(texture_ref, target, level, true);
   }
 
   if (copyX != x ||
       copyY != y ||
       copyWidth != width ||
       copyHeight != height) {
     // some part was clipped so clear the sub rect.
     uint32 pixels_size = 0;
     if (!GLES2Util::ComputeImageDataSizes(
         width, height, 1, format, type, state_.unpack_alignment, &pixels_size,
@@ skipping 584 matching lines @@
                        "GLImpl", static_cast<int>(gfx::GetGLImplementation()),
                        "width", (is_offscreen ? offscreen_size_.width() :
                                  surface_->GetSize().width()));
   TRACE_EVENT2("gpu", "GLES2DecoderImpl::DoSwapBuffers",
                "offscreen", is_offscreen,
                "frame", this_frame_number);
   {
     TRACE_EVENT_SYNTHETIC_DELAY("gpu.PresentingFrame");
   }
 
+  ScopedGPUTrace scoped_gpu_trace(gpu_tracer_.get(), kTraceDecoder,
+                                  "gpu_toplevel", "SwapBuffer");
+
   bool is_tracing;
   TRACE_EVENT_CATEGORY_GROUP_ENABLED(TRACE_DISABLED_BY_DEFAULT("gpu.debug"),
                                      &is_tracing);
   if (is_tracing) {
     ScopedFrameBufferBinder binder(this, GetBackbufferServiceId());
     gpu_state_tracer_->TakeSnapshotWithCurrentFramebuffer(
         is_offscreen ? offscreen_size_ : surface_->GetSize());
   }
 
   // If offscreen then don't actually SwapBuffers to the display. Just copy
@@ skipping 1874 matching lines @@
   }
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu