gpu: Support other buffer targets for ScopedBufferBinder

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 <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 529 matching lines @@
   void RestoreState(const ContextState* prev_state) override;
 
   void RestoreActiveTexture() const override { state_.RestoreActiveTexture(); }
   void RestoreAllTextureUnitBindings(
       const ContextState* prev_state) const override {
     state_.RestoreAllTextureUnitBindings(prev_state);
   }
   void RestoreActiveTextureUnitBinding(unsigned int target) const override {
     state_.RestoreActiveTextureUnitBinding(target);
   }
-  void RestoreBufferBinding(unsigned int target) const override {
-    state_.RestoreBufferBinding(target);
-  }
   void RestoreBufferBindings() const override {
     state_.RestoreBufferBindings();
   }
   void RestoreGlobalState() const override { state_.RestoreGlobalState(NULL); }
   void RestoreProgramBindings() const override {
     state_.RestoreProgramSettings(nullptr, false);
   }
   void RestoreTextureUnitBindings(unsigned unit) const override {
     state_.RestoreTextureUnitBindings(unit, NULL);
   }
   void RestoreVertexAttribArray(unsigned index) override {
     RestoreStateForAttrib(index, true);
   }
+  void RestoreBufferBinding(unsigned int target) override;
   void RestoreFramebufferBindings() const override;
   void RestoreRenderbufferBindings() override;
   void RestoreTextureState(unsigned service_id) const override;
 
   void ClearAllAttributes() const override;
   void RestoreAllAttributes() const override;
 
   QueryManager* GetQueryManager() override { return query_manager_.get(); }
   TransformFeedbackManager* GetTransformFeedbackManager() override {
     return transform_feedback_manager_.get();
@@ skipping 5017 matching lines @@
 void GLES2DecoderImpl::RestoreState(const ContextState* prev_state) {
   TRACE_EVENT1("gpu", "GLES2DecoderImpl::RestoreState",
                "context", logger_.GetLogPrefix());
   // Restore the Framebuffer first because of bugs in Intel drivers.
   // Intel drivers incorrectly clip the viewport settings to
   // the size of the current framebuffer object.
   RestoreFramebufferBindings();
   state_.RestoreState(prev_state);
 }
 
+void GLES2DecoderImpl::RestoreBufferBinding(unsigned int target) {
+  Buffer* bound_buffer =
+      buffer_manager()->GetBufferInfoForTarget(&state_, target);
+  if (target == GL_PIXEL_PACK_BUFFER) {
+    glPixelStorei(GL_PACK_ROW_LENGTH,

[piman, 2017/04/04 17:48:43]

We should only do these if we're on an ES3 context. Maybe you can use
state_.UpdatePackParameters() and state_.UpdateUnpackParameters().

[Chandan, 2017/04/04 18:18:45]

Thanks. As I see, these two methods are private. 
Will make these public?

[piman, 2017/04/04 19:59:14]

Alternatively, move this code to ContextState.

[Chandan, 2017/04/05 11:23:52]

The idea was to reuse BufferManager::GetBufferInfoForTarget instead of writing
similar code again to get bound buffer. However, it is not accessible from
ContextState. Therefore, I consciously did not move this code to ContextState to
avoid code duplication.
Another alternative I see is to pass BufferManager pointer to ContextState and
then access it there to get the buffer.
Making Update{Pack,UnPack}Parameters() public looks cleaner. WDYT?
I have uploaded patchset 2 which makes these 2 methods public in ContextState.
PTAL.

+                  bound_buffer ? state_.pack_row_length : 0);
+  } else if (target == GL_PIXEL_UNPACK_BUFFER) {
+    glPixelStorei(GL_UNPACK_ROW_LENGTH,
+                  bound_buffer ? state_.unpack_row_length : 0);
+    glPixelStorei(GL_UNPACK_IMAGE_HEIGHT,
+                  bound_buffer ? state_.unpack_image_height : 0);
+  }
+  glBindBuffer(target, bound_buffer ? bound_buffer->service_id() : 0);
+}
+
 void GLES2DecoderImpl::RestoreFramebufferBindings() const {
   GLuint service_id =
       framebuffer_state_.bound_draw_framebuffer.get()
           ? framebuffer_state_.bound_draw_framebuffer->service_id()
           : GetBackbufferServiceId();
   if (!SupportsSeparateFramebufferBinds()) {
     glBindFramebufferEXT(GL_FRAMEBUFFER, service_id);
   } else {
     glBindFramebufferEXT(GL_DRAW_FRAMEBUFFER, service_id);
     service_id = framebuffer_state_.bound_read_framebuffer.get()
@@ skipping 13953 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 "base/macros.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu