Update from https://crrev.com/306655

gpu/command_buffer/service/feature_info.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/feature_info.h"
 
 #include <set>
 
 #include "base/command_line.h"
 #include "base/macros.h"
@@ skipping 127 matching lines @@
       use_async_readpixels(false),
       map_buffer_range(false),
       ext_discard_framebuffer(false),
       angle_depth_texture(false),
       is_angle(false),
       is_swiftshader(false),
       angle_texture_usage(false),
       ext_texture_storage(false),
       chromium_path_rendering(false),
       blend_equation_advanced(false),
-      blend_equation_advanced_coherent(false) {
+      blend_equation_advanced_coherent(false),
+      ext_texture_rg(false),
+      enable_subscribe_uniform(false) {
 }
 
 FeatureInfo::Workarounds::Workarounds() :
 #define GPU_OP(type, name) name(false),
     GPU_DRIVER_BUG_WORKAROUNDS(GPU_OP)
 #undef GPU_OP
     max_texture_size(0),
     max_cube_map_texture_size(0),
     max_fragment_uniform_vectors(0),
     max_varying_vectors(0),
@@ skipping 13 matching lines @@
     std::string types = command_line.GetSwitchValueASCII(
         switches::kGpuDriverBugWorkarounds);
     StringToWorkarounds(types, &workarounds_);
   }
   feature_flags_.enable_shader_name_hashing =
       !command_line.HasSwitch(switches::kDisableShaderNameHashing);
 
   feature_flags_.is_swiftshader =
       (command_line.GetSwitchValueASCII(switches::kUseGL) == "swiftshader");
 
+  feature_flags_.enable_subscribe_uniform =
+      command_line.HasSwitch(switches::kEnableSubscribeUniformExtension);
+
   static const GLenum kAlphaTypes[] = {
       GL_UNSIGNED_BYTE,
   };
   static const GLenum kRGBTypes[] = {
       GL_UNSIGNED_BYTE,
       GL_UNSIGNED_SHORT_5_6_5,
   };
   static const GLenum kRGBATypes[] = {
       GL_UNSIGNED_BYTE,
       GL_UNSIGNED_SHORT_4_4_4_4,
@@ skipping 27 matching lines @@
   InitializeFeatures();
   return true;
 }
 
 bool FeatureInfo::Initialize(const DisallowedFeatures& disallowed_features) {
   disallowed_features_ = disallowed_features;
   InitializeFeatures();
   return true;
 }
 
+bool IsGL_REDSupportedOnFBOs() {
+  // Skia uses GL_RED with frame buffers, unfortunately, Mesa claims to support
+  // GL_EXT_texture_rg, but it doesn't support it on frame buffers.  To fix
+  // this, we try it, and if it fails, we don't expose GL_EXT_texture_rg.
+  GLint fb_binding = 0;
+  GLint tex_binding = 0;
+  glGetIntegerv(GL_FRAMEBUFFER_BINDING, &fb_binding);
+  glGetIntegerv(GL_TEXTURE_BINDING_2D, &tex_binding);
+
+  GLuint textureId = 0;
+  glGenTextures(1, &textureId);
+  glBindTexture(GL_TEXTURE_2D, textureId);
+  GLubyte data[1] = {0};
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RED_EXT, 1, 1, 0, GL_RED_EXT,
+               GL_UNSIGNED_BYTE, data);
+  GLuint textureFBOID = 0;
+  glGenFramebuffersEXT(1, &textureFBOID);
+  glBindFramebufferEXT(GL_FRAMEBUFFER, textureFBOID);
+  glFramebufferTexture2DEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                            textureId, 0);
+  bool result =
+      glCheckFramebufferStatusEXT(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_UNSUPPORTED;
+  glDeleteFramebuffersEXT(1, &textureFBOID);
+  glDeleteTextures(1, &textureId);
+
+  glBindFramebufferEXT(GL_FRAMEBUFFER, static_cast<GLuint>(fb_binding));
+  glBindTexture(GL_TEXTURE_2D, static_cast<GLuint>(tex_binding));
+
+  DCHECK(glGetError() == GL_NO_ERROR);
+
+  return result;
+}
+
 void FeatureInfo::InitializeFeatures() {
   // Figure out what extensions to turn on.
   StringSet extensions(
       reinterpret_cast<const char*>(glGetString(GL_EXTENSIONS)));
 
   const char* renderer_str =
       reinterpret_cast<const char*>(glGetString(GL_RENDERER));
   if (renderer_str) {
     feature_flags_.is_angle = StartsWithASCII(renderer_str, "ANGLE", true);
   }
@@ skipping 15 matching lines @@
   AddExtensionString("GL_CHROMIUM_get_error_query");
   AddExtensionString("GL_CHROMIUM_lose_context");
   AddExtensionString("GL_CHROMIUM_pixel_transfer_buffer_object");
   AddExtensionString("GL_CHROMIUM_rate_limit_offscreen_context");
   AddExtensionString("GL_CHROMIUM_resize");
   AddExtensionString("GL_CHROMIUM_resource_safe");
   AddExtensionString("GL_CHROMIUM_strict_attribs");
   AddExtensionString("GL_CHROMIUM_texture_mailbox");
   AddExtensionString("GL_EXT_debug_marker");
 
+  if (feature_flags_.enable_subscribe_uniform) {
+    AddExtensionString("GL_CHROMIUM_subscribe_uniform");
+  }
+
   // OES_vertex_array_object is emulated if not present natively,
   // so the extension string is always exposed.
   AddExtensionString("GL_OES_vertex_array_object");
 
   if (!disallowed_features_.gpu_memory_manager)
     AddExtensionString("GL_CHROMIUM_gpu_memory_manager");
 
   if (extensions.Contains("GL_ANGLE_translated_shader_source")) {
     feature_flags_.angle_translated_shader_source = true;
   }
@@ skipping 113 matching lines @@
   if (workarounds_.use_client_side_arrays_for_stream_buffers) {
     feature_flags_.native_vertex_array_object = false;
   }
 
   if (is_es3 || extensions.Contains("GL_OES_element_index_uint") ||
       gfx::HasDesktopGLFeatures()) {
     AddExtensionString("GL_OES_element_index_uint");
     validators_.index_type.AddValue(GL_UNSIGNED_INT);
   }
 
-  if (is_es3 || extensions.Contains("GL_EXT_sRGB") ||
-      gfx::HasDesktopGLFeatures()) {
+  // With EXT_sRGB, unsized SRGB_EXT and SRGB_ALPHA_EXT are accepted by the
+  // <format> and <internalformat> parameter of TexImage2D. GLES3 adds support
+  // for SRGB Textures but the accepted internal formats for TexImage2D are only
+  // sized formats GL_SRGB8 and GL_SRGB8_ALPHA8. Also, SRGB_EXT isn't a valid
+  // <format> in this case. So, even with GLES3 explicitly check for
+  // GL_EXT_sRGB.
+  if (((is_es3 || extensions.Contains("GL_OES_rgb8_rgba8")) &&
+      extensions.Contains("GL_EXT_sRGB")) || gfx::HasDesktopGLFeatures()) {
     AddExtensionString("GL_EXT_sRGB");
     texture_format_validators_[GL_SRGB_EXT].AddValue(GL_UNSIGNED_BYTE);
     texture_format_validators_[GL_SRGB_ALPHA_EXT].AddValue(GL_UNSIGNED_BYTE);
     validators_.texture_internal_format.AddValue(GL_SRGB_EXT);
     validators_.texture_internal_format.AddValue(GL_SRGB_ALPHA_EXT);
     validators_.texture_format.AddValue(GL_SRGB_EXT);
     validators_.texture_format.AddValue(GL_SRGB_ALPHA_EXT);
     validators_.render_buffer_format.AddValue(GL_SRGB8_ALPHA8_EXT);
     validators_.frame_buffer_parameter.AddValue(
         GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT);
@@ skipping 517 matching lines @@
   }
 
   if (extensions.Contains("GL_NV_path_rendering")) {
     if (extensions.Contains("GL_EXT_direct_state_access") || is_es3) {
       AddExtensionString("GL_CHROMIUM_path_rendering");
       feature_flags_.chromium_path_rendering = true;
       validators_.g_l_state.AddValue(GL_PATH_MODELVIEW_MATRIX_CHROMIUM);
       validators_.g_l_state.AddValue(GL_PATH_PROJECTION_MATRIX_CHROMIUM);
     }
   }
+
+  if ((is_es3 || extensions.Contains("GL_EXT_texture_rg") ||
+       extensions.Contains("GL_ARB_texture_rg")) &&
+      IsGL_REDSupportedOnFBOs()) {
+    feature_flags_.ext_texture_rg = true;
+    AddExtensionString("GL_EXT_texture_rg");
+
+    validators_.texture_format.AddValue(GL_RED_EXT);
+    validators_.texture_format.AddValue(GL_RG_EXT);
+    validators_.texture_internal_format.AddValue(GL_RED_EXT);
+    validators_.texture_internal_format.AddValue(GL_RG_EXT);
+    validators_.read_pixel_format.AddValue(GL_RED_EXT);
+    validators_.read_pixel_format.AddValue(GL_RG_EXT);
+    validators_.render_buffer_format.AddValue(GL_R8_EXT);
+    validators_.render_buffer_format.AddValue(GL_RG8_EXT);
+
+    texture_format_validators_[GL_RED_EXT].AddValue(GL_UNSIGNED_BYTE);
+    texture_format_validators_[GL_RG_EXT].AddValue(GL_UNSIGNED_BYTE);
+
+    if (enable_texture_float) {
+      texture_format_validators_[GL_RED_EXT].AddValue(GL_FLOAT);
+      texture_format_validators_[GL_RG_EXT].AddValue(GL_FLOAT);
+    }
+    if (enable_texture_half_float) {
+      texture_format_validators_[GL_RED_EXT].AddValue(GL_HALF_FLOAT_OES);
+      texture_format_validators_[GL_RG_EXT].AddValue(GL_HALF_FLOAT_OES);
+    }
+  }
 }
 
 void FeatureInfo::AddExtensionString(const char* s) {
   std::string str(s);
   size_t pos = extensions_.find(str);
   while (pos != std::string::npos &&
          pos + str.length() < extensions_.length() &&
          extensions_.substr(pos + str.length(), 1) != " ") {
     // This extension name is a substring of another.
     pos = extensions_.find(str, pos + str.length());
   }
   if (pos == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 FeatureInfo::~FeatureInfo() {
 }
 
 }  // namespace gles2
 }  // namespace gpu