Add more precise DCHECKs to float feature info

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 <stddef.h>
 
 #include <set>
 #include <vector>
@@ skipping 1360 matching lines @@
       extensions.Contains("GL_CHROMIUM_copy_compressed_texture");
   feature_flags_.angle_client_arrays =
       extensions.Contains("GL_ANGLE_client_arrays");
   feature_flags_.angle_request_extension =
       extensions.Contains("GL_ANGLE_request_extension");
   feature_flags_.ext_debug_marker = extensions.Contains("GL_EXT_debug_marker");
 }
 
 void FeatureInfo::InitializeFloatAndHalfFloatFeatures(
     const StringSet& extensions) {
+  // No errors should be present before running this function.
+  DCHECK_EQ(glGetError(), static_cast<GLuint>(GL_NO_ERROR));
+
   // Check if we should allow GL_OES_texture_float, GL_OES_texture_half_float,
   // GL_OES_texture_float_linear, GL_OES_texture_half_float_linear
   bool enable_texture_float = false;
   bool enable_texture_float_linear = false;
   bool enable_texture_half_float = false;
   bool enable_texture_half_float_linear = false;
   bool enable_ext_color_buffer_float = false;
   bool enable_ext_color_buffer_half_float = false;
 
   bool may_enable_chromium_color_buffer_float = false;
@@ skipping 105 matching lines @@
       };
       GLenum formats[] = {
           GL_RED, GL_RG, GL_RGBA, GL_RED, GL_RG, GL_RGB,
       };
       DCHECK_EQ(arraysize(internal_formats), arraysize(formats));
       for (size_t i = 0; i < arraysize(formats); ++i) {
         glTexImage2D(GL_TEXTURE_2D, 0, internal_formats[i], width, width, 0,
                      formats[i], GL_FLOAT, NULL);
         full_float_support &= glCheckFramebufferStatusEXT(GL_FRAMEBUFFER) ==
                               GL_FRAMEBUFFER_COMPLETE;
+        DCHECK_EQ(glGetError(), static_cast<GLuint>(GL_NO_ERROR))
+            << " with internal format " << internal_formats[i] << " and format "
+            << formats[i] << ".";
       }
       enable_ext_color_buffer_float = full_float_support;
     }
     // Likewise for EXT_color_buffer_half_float on ES2 contexts.
     if (IsWebGL1OrES2Context() && !enable_ext_color_buffer_half_float) {
       bool full_half_float_support = true;
       GLenum internal_formats[] = {
           GL_R16F, GL_RG16F, GL_RGBA16F,
       };
       GLenum formats[] = {
           GL_RED, GL_RG, GL_RGBA,
       };
       GLenum data_type = GL_FLOAT;
       if (gl_version_info_->is_es2)
         data_type = GL_HALF_FLOAT_OES;
       if (gl_version_info_->is_es3)
         data_type = GL_HALF_FLOAT;
       DCHECK_EQ(arraysize(internal_formats), arraysize(formats));
       for (size_t i = 0; i < arraysize(formats); ++i) {
         glTexImage2D(GL_TEXTURE_2D, 0, internal_formats[i], width, width, 0,
                      formats[i], data_type, NULL);
         full_half_float_support &=
             glCheckFramebufferStatusEXT(GL_FRAMEBUFFER) ==
             GL_FRAMEBUFFER_COMPLETE;
+        DCHECK_EQ(glGetError(), static_cast<GLuint>(GL_NO_ERROR))
+            << " with internal format " << internal_formats[i] << " and format "
+            << formats[i] << ".";
       }
       enable_ext_color_buffer_half_float = full_half_float_support;
     }
 
     glDeleteFramebuffersEXT(1, &fb_id);
     glDeleteTextures(1, &tex_id);
 
     glBindFramebufferEXT(GL_FRAMEBUFFER, static_cast<GLuint>(fb_binding));
     glBindTexture(GL_TEXTURE_2D, static_cast<GLuint>(tex_binding));
 
@@ skipping 156 matching lines @@
   if (pos == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 FeatureInfo::~FeatureInfo() {
 }
 
 }  // namespace gles2
 }  // namespace gpu