Add command buffer support for GL_RGB CHROMIUM image emulation.

gpu/command_buffer/service/texture_manager.cc

Index: gpu/command_buffer/service/texture_manager.cc
diff --git a/gpu/command_buffer/service/texture_manager.cc b/gpu/command_buffer/service/texture_manager.cc
index 8297c6d04556fbdee6806487b6a81552810637e3..e33093dacab41b6d998300f1dfdb9f9f4f60b699 100644
--- a/gpu/command_buffer/service/texture_manager.cc
+++ b/gpu/command_buffer/service/texture_manager.cc
@@ -65,6 +65,7 @@ struct TextureSignature {
   bool can_render_;
   bool can_render_to_;
   bool npot_;
+  bool emulating_rgb_;
 
   // Since we will be hashing this signature structure, the padding must be
   // zero initialized. Although the C++11 specifications specify that this is
@@ -86,7 +87,8 @@ struct TextureSignature {
                    bool has_image,
                    bool can_render,
                    bool can_render_to,
-                   bool npot) {
+                   bool npot,
+                   bool emulating_rgb) {
     memset(this, 0, sizeof(TextureSignature));
     target_ = target;
     level_ = level;
@@ -113,6 +115,7 @@ struct TextureSignature {
     can_render_ = can_render;
     can_render_to_ = can_render_to;
     npot_ = npot;
+    emulating_rgb_ = emulating_rgb;
   }
 };
 
@@ -376,7 +379,8 @@ Texture::Texture(GLuint service_id)
       estimated_size_(0),
       can_render_condition_(CAN_RENDER_ALWAYS),
       texture_max_anisotropy_initialized_(false),
-      compatibility_swizzle_(nullptr) {}
+      compatibility_swizzle_(nullptr),
+      emulating_rgb_(false) {}
 
 Texture::~Texture() {
   if (mailbox_manager_)
@@ -587,7 +591,8 @@ void Texture::AddToSignature(
                                   info.image.get() != NULL,
                                   CanRender(feature_info),
                                   CanRenderTo(feature_info, level),
-                                  npot_);
+                                  npot_,
+                                  emulating_rgb_);
 
   signature->append(TextureTag, sizeof(TextureTag));
   signature->append(reinterpret_cast<const char*>(&signature_data),
@@ -866,6 +871,18 @@ void Texture::UpdateHasImages() {
     (*it)->manager()->UpdateNumImages(delta);
 }
 
+void Texture::UpdateEmulatingRGB() {
+  for (const FaceInfo& face_info : face_infos_) {
+    for (const LevelInfo& level_info : face_info.level_infos) {
+      if (level_info.image && level_info.image->EmulatingRGB())
+        emulating_rgb_ = true;

[erikchen, 2016/04/15 18:54:07]

piman: Request for comment.

This code is never run on non-Mac platforms.

MSVC doesn't like this:
"""
e:\b\build\slave\win\build\src\gpu\command_buffer\service\texture_manager.cc(876)
: error C2220: warning treated as error - no 'object' file generated
e:\b\build\slave\win\build\src\gpu\command_buffer\service\texture_manager.cc(876)
: warning C4702: unreachable code
"""

I can either:
1) Add some #pragmas to disable the warning on Windows
2) #ifdef out the code on Windows.
3) #ifdef out the code on non-OSX.

Normally I'd go with (2) and not even bother with a second request for review,
but you seem to have strong opinions about the presence of #ifdefs. Did you have
any opinions on this subject?

[piman, 2016/04/15 19:20:24]

Why is this not run on non-mac platforms? Is it because the compiler is able to
see that there's no implementation of GLImage that returns true here?

I would prefer disabling the warning, ifdefs seem out of place. It's none of
your business, compiler. Optimize it, fine, but don't warn.

+        return;
+    }
+  }
+  emulating_rgb_ = false;
+}
+
+
 void Texture::IncAllFramebufferStateChangeCount() {
   for (RefSet::iterator it = refs_.begin(); it != refs_.end(); ++it)
     (*it)->manager()->IncFramebufferStateChangeCount();
@@ -1445,6 +1462,7 @@ void Texture::SetLevelImageInternal(GLenum target,
 
   UpdateCanRenderCondition();
   UpdateHasImages();
+  UpdateEmulatingRGB();
 }
 
 void Texture::SetLevelImage(GLenum target,
@@ -1621,6 +1639,10 @@ void Texture::ApplyFormatWorkarounds(FeatureInfo* feature_info) {
   }
 }
 
+bool Texture::EmulatingRGB() {
+  return emulating_rgb_;
+}
+
 TextureRef::TextureRef(TextureManager* manager,
                        GLuint client_id,
                        Texture* texture)