Don't enable shader extenstions in WebGL 2 when they are already core.

BUG=295792
TEST=webgl2_conformance
R=bajones@chromium.org

Review URL: https://codereview.chromium.org/1625643003

Cr-Commit-Position: refs/heads/master@{#371627}

content/test/gpu/gpu_tests/webgl2_conformance_expectations.py

@@ -79,14 +79,12 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
 
     self.Fail('conformance2/glsl3/array-complex-indexing.html', bug=483282)
     self.Fail('conformance2/glsl3/forbidden-operators.html', bug=483282)
-    self.Fail('conformance2/extensions/promoted-extensions-in-shaders.html',
-        bug=295792)
     self.Fail('conformance2/samplers/sampler-drawing-test.html', bug=483282)
     self.Fail('conformance2/state/gl-object-get-calls.html', bug=483282)
     # Note that this test fails on ['win', 'intel'] with bug=483282
     self.Fail('conformance2/buffers/uniform-buffers.html', bug=577368)
 
-    # Windows and Mac.
+    # Windows only.
     self.Fail('conformance2/textures/canvas/tex-image-and-sub-image-2d' +
         '-with-canvas-r8-red-unsigned_byte.html',
         ['win'], bug=483282)
@@ -197,7 +195,6 @@ class WebGL2ConformanceExpectations(WebGLConformanceExpectations):
         '-with-webgl-canvas-rgba4-rgba-unsigned_short_4_4_4_4.html',
         ['win'], bug=483282)
 
-    # Windows only.
     self.Skip('deqp/functional/gles3/readpixel.html', ['win'], bug=483282)
     self.Skip('deqp/functional/gles3/texturestatequery.html',
         ['win'], bug=483282)

gpu/command_buffer/service/gles2_cmd_decoder.cc

@@ -3202,47 +3202,49 @@ bool GLES2DecoderImpl::InitializeShaderTranslator() {
   resources.FragmentPrecisionHigh =
       PrecisionMeetsSpecForHighpFloat(range[0], range[1], precision);
 
-  if (feature_info_->IsWebGLContext()) {
-    resources.OES_standard_derivatives = derivatives_explicitly_enabled_;
-    resources.EXT_frag_depth = frag_depth_explicitly_enabled_;
-    resources.EXT_draw_buffers = draw_buffers_explicitly_enabled_;
-    if (!draw_buffers_explicitly_enabled_)
-      resources.MaxDrawBuffers = 1;
-    resources.EXT_shader_texture_lod = shader_texture_lod_explicitly_enabled_;
-    resources.NV_draw_buffers =
-        draw_buffers_explicitly_enabled_ && features().nv_draw_buffers;
-  } else {
-    resources.OES_standard_derivatives =
-        features().oes_standard_derivatives ? 1 : 0;
-    resources.ARB_texture_rectangle =
-        features().arb_texture_rectangle ? 1 : 0;
-    resources.OES_EGL_image_external =
-        features().oes_egl_image_external ? 1 : 0;
-    resources.EXT_draw_buffers =
-        features().ext_draw_buffers ? 1 : 0;
-    resources.EXT_frag_depth =
-        features().ext_frag_depth ? 1 : 0;
-    resources.EXT_shader_texture_lod =
-        features().ext_shader_texture_lod ? 1 : 0;
-    resources.NV_draw_buffers =
-        features().nv_draw_buffers ? 1 : 0;
-    resources.EXT_blend_func_extended =
-        features().ext_blend_func_extended ? 1 : 0;
-  }
-
   ShShaderSpec shader_spec;
   switch (feature_info_->context_type()) {
     case CONTEXT_TYPE_WEBGL1:
       shader_spec = SH_WEBGL_SPEC;
+      resources.OES_standard_derivatives = derivatives_explicitly_enabled_;
+      resources.EXT_frag_depth = frag_depth_explicitly_enabled_;
+      resources.EXT_draw_buffers = draw_buffers_explicitly_enabled_;
+      if (!draw_buffers_explicitly_enabled_)
+        resources.MaxDrawBuffers = 1;
+      resources.EXT_shader_texture_lod = shader_texture_lod_explicitly_enabled_;
+      resources.NV_draw_buffers =
+          draw_buffers_explicitly_enabled_ && features().nv_draw_buffers;
       break;
     case CONTEXT_TYPE_WEBGL2:
       shader_spec = SH_WEBGL2_SPEC;
       break;
     case CONTEXT_TYPE_OPENGLES2:
       shader_spec = SH_GLES2_SPEC;
+      resources.OES_standard_derivatives =
+          features().oes_standard_derivatives ? 1 : 0;
+      resources.ARB_texture_rectangle =
+          features().arb_texture_rectangle ? 1 : 0;
+      resources.OES_EGL_image_external =
+          features().oes_egl_image_external ? 1 : 0;
+      resources.EXT_draw_buffers =
+          features().ext_draw_buffers ? 1 : 0;
+      resources.EXT_frag_depth =
+          features().ext_frag_depth ? 1 : 0;
+      resources.EXT_shader_texture_lod =
+          features().ext_shader_texture_lod ? 1 : 0;
+      resources.NV_draw_buffers =
+          features().nv_draw_buffers ? 1 : 0;
+      resources.EXT_blend_func_extended =
+          features().ext_blend_func_extended ? 1 : 0;
       break;
     case CONTEXT_TYPE_OPENGLES3:
       shader_spec = SH_GLES3_SPEC;
+      resources.ARB_texture_rectangle =
+          features().arb_texture_rectangle ? 1 : 0;
+      resources.OES_EGL_image_external =
+          features().oes_egl_image_external ? 1 : 0;
+      resources.EXT_blend_func_extended =
+          features().ext_blend_func_extended ? 1 : 0;
       break;
     default:
       NOTREACHED();
@@ -9985,8 +9987,8 @@ error::Error GLES2DecoderImpl::HandleGetString(uint32_t immediate_data_size,
       break;
     case GL_EXTENSIONS:
       {
-        // For WebGL contexts, strip out the OES derivatives and
-        // EXT frag depth extensions if they have not been enabled.
+        // For WebGL contexts, strip out shader extensions if they have not
+        // been enabled on WebGL1 or no longer exist (become core) in WebGL2.
         if (feature_info_->IsWebGLContext()) {
           extensions = feature_info_->extensions();
           if (!derivatives_explicitly_enabled_) {
@@ -12330,7 +12332,7 @@ error::Error GLES2DecoderImpl::HandleRequestExtensionCHROMIUM(
   bool desire_frag_depth = false;
   bool desire_draw_buffers = false;
   bool desire_shader_texture_lod = false;
-  if (feature_info_->IsWebGLContext()) {
+  if (feature_info_->context_type() == CONTEXT_TYPE_WEBGL1) {
     desire_standard_derivatives =
         feature_str.find("GL_OES_standard_derivatives") != std::string::npos;
     desire_frag_depth =