Added ScopedSetActiveTexture to auto reset activeTexture to GL_TEXTURE0.

cc/resources/resource_provider.cc

 // Copyright 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 "cc/resources/resource_provider.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/containers/hash_tables.h"
@@ skipping 36 matching lines @@
       break;
   }
 
   return storage_format;
 }
 
 bool IsTextureFormatSupportedForStorage(GLenum format) {
   return (format == GL_RGBA || format == GL_BGRA_EXT);
 }
 
+class ScopedSetActiveTexture {
+ public:
+  ScopedSetActiveTexture(WebGraphicsContext3D* context3d, GLenum unit)
+      : context3d_(context3d), unit_(unit) {
+    DCHECK_EQ(GL_TEXTURE0, ResourceProvider::GetActiveTextureUnit(context3d_));
+
+    if (unit_ != GL_TEXTURE0)
+      GLC(context3d_, context3d_->activeTexture(unit_));
+  }
+
+  ~ScopedSetActiveTexture() {
+    // Active unit being GL_TEXTURE0 is effectively the ground state.
+    if (unit_ != GL_TEXTURE0)
+      GLC(context3d_, context3d_->activeTexture(GL_TEXTURE0));
+  }
+
+ private:
+  WebGraphicsContext3D* context3d_;
+  GLenum unit_;
+};
+
 }  // namespace
 
 ResourceProvider::Resource::Resource()
     : gl_id(0),
       gl_pixel_buffer_id(0),
       gl_upload_query_id(0),
       pixels(NULL),
       pixel_buffer(NULL),
       lock_for_read_count(0),
       imported_count(0),
@@ skipping 1023 matching lines @@
                                        GLenum target,
                                        GLenum unit,
                                        GLenum filter) {
   DCHECK(thread_checker_.CalledOnValidThread());
   WebGraphicsContext3D* context3d = Context3d();
   ResourceMap::iterator it = resources_.find(resource_id);
   DCHECK(it != resources_.end());
   Resource* resource = &it->second;
   DCHECK(resource->lock_for_read_count);
   DCHECK(!resource->locked_for_write || resource->set_pixels_completion_forced);
-  DCHECK_EQ(GL_TEXTURE0, GetActiveTextureUnit(context3d));
 
-  if (unit != GL_TEXTURE0)
-    GLC(context3d, context3d->activeTexture(unit));
+  ScopedSetActiveTexture scoped_active_tex(context3d, unit);
   GLC(context3d, context3d->bindTexture(target, resource->gl_id));
   if (filter != resource->filter) {
     GLC(context3d, context3d->texParameteri(target,
                                             GL_TEXTURE_MIN_FILTER,
                                             filter));
     GLC(context3d, context3d->texParameteri(target,
                                             GL_TEXTURE_MAG_FILTER,
                                             filter));
     resource->filter = filter;
   }
 
   if (resource->image_id)
     context3d->bindTexImage2DCHROMIUM(target, resource->image_id);
-
-  // Active unit being GL_TEXTURE0 is effectively the ground state.
-  if (unit != GL_TEXTURE0)
-    GLC(context3d, context3d->activeTexture(GL_TEXTURE0));
 }
 
 void ResourceProvider::UnbindForSampling(
     ResourceProvider::ResourceId resource_id, GLenum target, GLenum unit) {
   DCHECK(thread_checker_.CalledOnValidThread());
   ResourceMap::iterator it = resources_.find(resource_id);
   DCHECK(it != resources_.end());
   Resource* resource = &it->second;
 
   if (!resource->image_id)
     return;
 
   WebGraphicsContext3D* context3d = Context3d();
-  DCHECK_EQ(GL_TEXTURE0, GetActiveTextureUnit(context3d));
-  if (unit != GL_TEXTURE0)
-    GLC(context3d, context3d->activeTexture(unit));
+  ScopedSetActiveTexture scoped_active_tex(context3d, unit);
   context3d->releaseTexImage2DCHROMIUM(target, resource->image_id);
-  // Active unit being GL_TEXTURE0 is effectively the ground state.
-  if (unit != GL_TEXTURE0)
-    GLC(context3d, context3d->activeTexture(GL_TEXTURE0));
 }
 
 void ResourceProvider::BeginSetPixels(ResourceId id) {
   Resource* resource = GetResource(id);
   DCHECK(!resource->pending_set_pixels);
 
   LazyCreate(resource);
   DCHECK(resource->gl_id || resource->allocated);
   DCHECK(ReadLockFenceHasPassed(resource));
   DCHECK(!resource->image_id);
@@ skipping 265 matching lines @@
   context->getIntegerv(GL_ACTIVE_TEXTURE, &active_unit);
   return active_unit;
 }
 
 WebKit::WebGraphicsContext3D* ResourceProvider::Context3d() const {
   ContextProvider* context_provider = output_surface_->context_provider();
   return context_provider ? context_provider->Context3d() : NULL;
 }
 
 }  // namespace cc