Update from https://crrev.com/308331

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index f97710e86a61009ce7b6b54517f63040d5f8cb3b..7ea1a06e73bdf90cbccf38f381c3188bc6d7f7ac 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -1473,6 +1473,11 @@ class GLES2DecoderImpl : public GLES2Decoder,
   // Wrapper for glReleaseShaderCompiler.
   void DoReleaseShaderCompiler() { }
 
+  // Wrappers for glSamplerParameter*v functions.
+  void DoSamplerParameterfv(
+      GLuint sampler, GLenum pname, const GLfloat* params);
+  void DoSamplerParameteriv(GLuint sampler, GLenum pname, const GLint* params);
+
   // Wrappers for glTexParameter functions.
   void DoTexParameterf(GLenum target, GLenum pname, GLfloat param);
   void DoTexParameteri(GLenum target, GLenum pname, GLint param);
@@ -2955,6 +2960,10 @@ bool GLES2DecoderImpl::InitializeShaderTranslator() {
   if (workarounds().regenerate_struct_names)
     driver_bug_workarounds |= SH_REGENERATE_STRUCT_NAMES;
 
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEmulateShaderPrecision))
+    resources.WEBGL_debug_shader_precision = true;
+
   vertex_translator_ = shader_translator_cache()->GetTranslator(
       GL_VERTEX_SHADER,
       shader_spec,
@@ -4269,6 +4278,14 @@ void GLES2DecoderImpl::SetIgnoreCachedStateForTest(bool ignore) {
 void GLES2DecoderImpl::OnFboChanged() const {
   if (workarounds().restore_scissor_on_fbo_change)
     state_.fbo_binding_for_scissor_workaround_dirty_ = true;
+
+  if (workarounds().gl_begin_gl_end_on_fbo_change_to_backbuffer) {
+    GLint bound_fbo_unsigned = -1;
+    glGetIntegerv(GL_FRAMEBUFFER_BINDING_EXT, &bound_fbo_unsigned);
+    GLuint bound_fbo = static_cast<GLuint>(bound_fbo_unsigned);
+    if (surface_ && surface_->GetBackingFrameBufferObject() == bound_fbo)
+      surface_->NotifyWasBound();
+  }
 }
 
 // Called after the FBO is checked for completeness.
@@ -5858,6 +5875,18 @@ void GLES2DecoderImpl::DoLinkProgram(GLuint program_id) {
   ExitCommandProcessingEarly();
 };
 
+void GLES2DecoderImpl::DoSamplerParameterfv(
+    GLuint sampler, GLenum pname, const GLfloat* params) {
+  DCHECK(params);
+  glSamplerParameterf(sampler, pname, params[0]);
+}
+
+void GLES2DecoderImpl::DoSamplerParameteriv(
+    GLuint sampler, GLenum pname, const GLint* params) {
+  DCHECK(params);
+  glSamplerParameteri(sampler, pname, params[0]);
+}
+
 void GLES2DecoderImpl::DoTexParameterf(
     GLenum target, GLenum pname, GLfloat param) {
   TextureRef* texture = texture_manager()->GetTextureInfoForTarget(