SwiftShader WebGL fallback fix for MacOS

The SwiftShader library was failing to load properly when used as a WebGL
fallback because of a sandboxing issue. This cl works around that issue
by changing where the SwiftShader initializatin is done.

Credit to zmo@ for this fix, which I cherry picked from:
https://chromium-review.googlesource.com/c/chromium/src/+/1005017/20..21

Fixes:
gpu_tests.gpu_process_integration_test.GpuProcessIntegrationTest.GpuProcess_feature_status_under_swiftshader

Bug: chromium:726075
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I56a00cef70cb630bbf6d5fe7f342a8d5b1c2211d
Reviewed-on: https://chromium-review.googlesource.com/1042496
Commit-Queue: Alexis Hétu <sugoi@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#556163}

content/common/sandbox_init_mac.cc

@@ -51,16 +51,22 @@ base::OnceClosure MaybeWrapWithGPUSandboxHook(
               gpu::SwitchValueToGpuPreferences(value, &gpu_preferences);
           CHECK(success);
         }
+        bool needs_more_info = false;
         gpu::GpuFeatureInfo gpu_feature_info = gpu::ComputeGpuFeatureInfo(
             gpu_info, gpu_preferences.ignore_gpu_blacklist,
             gpu_preferences.disable_gpu_driver_bug_workarounds,
             gpu_preferences.log_gpu_control_list_decisions, command_line,
-            nullptr);
+            &needs_more_info);
         gpu::CacheGpuFeatureInfo(gpu_feature_info);
         if (gpu::SwitchableGPUsSupported(gpu_info, *command_line)) {
           gpu::InitializeSwitchableGPUs(
               gpu_feature_info.enabled_gpu_driver_bug_workarounds);
         }
+        // Calling ShouldEnableSwiftShader will append the proper command line
+        // switch in order to enable SwiftShader if required.
+        gpu::ShouldEnableSwiftShader(
+            command_line, gpu_feature_info,
+            gpu_preferences.disable_software_rasterizer, needs_more_info);
         // Preload either the desktop GL or the osmesa so, depending on the
         // --use-gl flag.
         gl::init::InitializeGLOneOff();

gpu/config/gpu_util.cc

@@ -11,6 +11,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/stringprintf.h"
+#include "build/build_config.h"
 #include "gpu/config/gpu_blacklist.h"
 #include "gpu/config/gpu_crash_keys.h"
 #include "gpu/config/gpu_driver_bug_list.h"
@@ -20,6 +21,7 @@
 #include "gpu/config/gpu_info_collector.h"
 #include "gpu/config/gpu_switches.h"
 #include "ui/gl/extension_set.h"
+#include "ui/gl/gl_features.h"
 #include "ui/gl/gl_switches.h"
 
 #if defined(OS_ANDROID)
@@ -481,4 +483,27 @@ bool InitializeGLThreadSafe(base::CommandLine* command_line,
 }
 #endif  // OS_ANDROID
 
+bool ShouldEnableSwiftShader(base::CommandLine* command_line,
+                             const GpuFeatureInfo& gpu_feature_info,
+                             bool disable_software_rasterizer,
+                             bool blacklist_needs_more_info) {
+#if BUILDFLAG(ENABLE_SWIFTSHADER)
+  if (disable_software_rasterizer)
+    return false;
+  // Don't overwrite user preference.
+  if (command_line->HasSwitch(switches::kUseGL))
+    return false;
+  if (!blacklist_needs_more_info &&
+      gpu_feature_info.status_values[GPU_FEATURE_TYPE_ACCELERATED_WEBGL] !=
+          kGpuFeatureStatusEnabled) {
+    command_line->AppendSwitchASCII(
+        switches::kUseGL, gl::kGLImplementationSwiftShaderForWebGLName);
+    return true;
+  }
+  return false;
+#else
+  return false;
+#endif
+}
+
 }  // namespace gpu

gpu/config/gpu_util.h

@@ -68,6 +68,13 @@ GPU_EXPORT bool InitializeGLThreadSafe(base::CommandLine* command_line,
                                        GpuFeatureInfo* out_gpu_feature_info);
 #endif  // OS_ANDROID
 
+// Returns whether SwiftShader should be enabled. If true, the proper command
+// line switch to enable SwiftShader will be appended to 'command_line'.
+GPU_EXPORT bool ShouldEnableSwiftShader(base::CommandLine* command_line,
+                                        const GpuFeatureInfo& gpu_feature_info,
+                                        bool disable_software_rasterizer,
+                                        bool blacklist_needs_more_info);
+
 }  // namespace gpu
 
 #endif  // GPU_CONFIG_GPU_UTIL_H_

gpu/ipc/service/gpu_init.cc

@@ -123,6 +123,8 @@ bool GpuInit::InitializeAndStartSandbox(base::CommandLine* command_line,
 #endif  // !OS_ANDROID && !IS_CHROMECAST
   gpu_info_.in_process_gpu = false;
 
+  bool use_swiftshader = false;
+
   // GL bindings may have already been initialized, specifically on MacOSX.
   bool gl_initialized = gl::GetGLImplementation() != gl::kGLImplementationNone;
   if (!gl_initialized) {
@@ -131,6 +133,10 @@ bool GpuInit::InitializeAndStartSandbox(base::CommandLine* command_line,
       gpu::InitializeSwitchableGPUs(
           gpu_feature_info_.enabled_gpu_driver_bug_workarounds);
     }
+  } else if (gl::GetGLImplementation() == gl::kGLImplementationSwiftShaderGL &&
+             command_line->GetSwitchValueASCII(switches::kUseGL) !=
+                 gl::kGLImplementationSwiftShaderName) {
+    use_swiftshader = true;
   }
 
   bool enable_watchdog = !gpu_preferences.disable_gpu_watchdog &&
@@ -194,8 +200,13 @@ bool GpuInit::InitializeAndStartSandbox(base::CommandLine* command_line,
   ui::OzonePlatform::InitializeForGPU(params);
 #endif
 
-  bool use_swiftshader = ShouldEnableSwiftShader(command_line, needs_more_info);
-  if (gl_initialized && use_swiftshader) {
+  if (!use_swiftshader) {
+    use_swiftshader = ShouldEnableSwiftShader(
+        command_line, gpu_feature_info_,
+        gpu_preferences.disable_software_rasterizer, needs_more_info);
+  }
+  if (gl_initialized && use_swiftshader &&
+      gl::GetGLImplementation() != gl::kGLImplementationSwiftShaderGL) {
     gl::init::ShutdownGL(true);
     gl_initialized = false;
   }
@@ -222,7 +233,9 @@ bool GpuInit::InitializeAndStartSandbox(base::CommandLine* command_line,
         gpu_info_, gpu_preferences.ignore_gpu_blacklist,
         gpu_preferences.disable_gpu_driver_bug_workarounds,
         gpu_preferences.log_gpu_control_list_decisions, command_line, nullptr);
-    use_swiftshader = ShouldEnableSwiftShader(command_line, false);
+    use_swiftshader = ShouldEnableSwiftShader(
+        command_line, gpu_feature_info_,
+        gpu_preferences.disable_software_rasterizer, false);
     if (use_swiftshader) {
       gl::init::ShutdownGL(true);
       if (!gl::init::InitializeGLNoExtensionsOneOff()) {
@@ -304,7 +317,9 @@ void GpuInit::InitializeInProcess(base::CommandLine* command_line,
                                   const GpuPreferences& gpu_preferences) {
   gpu_preferences_ = gpu_preferences;
   init_successful_ = true;
-  DCHECK(!ShouldEnableSwiftShader(command_line, false));
+  DCHECK(!ShouldEnableSwiftShader(command_line, gpu_feature_info_,
+                                  gpu_preferences.disable_software_rasterizer,
+                                  false));
 
   InitializeGLThreadSafe(command_line, gpu_preferences.ignore_gpu_blacklist,
                          gpu_preferences.disable_gpu_driver_bug_workarounds,
@@ -346,7 +361,9 @@ void GpuInit::InitializeInProcess(base::CommandLine* command_line,
   }
 #endif  // !IS_CHROMECAST
 
-  bool use_swiftshader = ShouldEnableSwiftShader(command_line, needs_more_info);
+  bool use_swiftshader = ShouldEnableSwiftShader(
+      command_line, gpu_feature_info_,
+      gpu_preferences.disable_software_rasterizer, needs_more_info);
   if (!gl::init::InitializeGLNoExtensionsOneOff()) {
     VLOG(1) << "gl::init::InitializeGLNoExtensionsOneOff failed";
     return;
@@ -359,7 +376,9 @@ void GpuInit::InitializeInProcess(base::CommandLine* command_line,
         gpu_info_, gpu_preferences.ignore_gpu_blacklist,
         gpu_preferences.disable_gpu_driver_bug_workarounds,
         gpu_preferences.log_gpu_control_list_decisions, command_line, nullptr);
-    use_swiftshader = ShouldEnableSwiftShader(command_line, false);
+    use_swiftshader = ShouldEnableSwiftShader(
+        command_line, gpu_feature_info_,
+        gpu_preferences.disable_software_rasterizer, false);
     if (use_swiftshader) {
       gl::init::ShutdownGL(true);
       if (!gl::init::InitializeGLNoExtensionsOneOff()) {
@@ -387,27 +406,6 @@ void GpuInit::InitializeInProcess(base::CommandLine* command_line,
 }
 #endif  // OS_ANDROID
 
-bool GpuInit::ShouldEnableSwiftShader(base::CommandLine* command_line,
-                                      bool blacklist_needs_more_info) {
-#if BUILDFLAG(ENABLE_SWIFTSHADER)
-  if (gpu_preferences_.disable_software_rasterizer)
-    return false;
-  // Don't overwrite user preference.
-  if (command_line->HasSwitch(switches::kUseGL))
-    return false;
-  if (!blacklist_needs_more_info &&
-      gpu_feature_info_.status_values[GPU_FEATURE_TYPE_ACCELERATED_WEBGL] !=
-          kGpuFeatureStatusEnabled) {
-    command_line->AppendSwitchASCII(
-        switches::kUseGL, gl::kGLImplementationSwiftShaderForWebGLName);
-    return true;
-  }
-  return false;
-#else
-  return false;
-#endif
-}
-
 void GpuInit::AdjustInfoToSwiftShader() {
   gpu_info_for_hardware_gpu_ = gpu_info_;
   gpu_feature_info_for_hardware_gpu_ = gpu_feature_info_;

gpu/ipc/service/gpu_init.h

@@ -74,8 +74,6 @@ class GPU_IPC_SERVICE_EXPORT GpuInit {
   base::Optional<GPUInfo> gpu_info_for_hardware_gpu_;
   base::Optional<GpuFeatureInfo> gpu_feature_info_for_hardware_gpu_;
 
-  bool ShouldEnableSwiftShader(base::CommandLine* command_line,
-                               bool blacklist_needs_more_info);
   void AdjustInfoToSwiftShader();
   void AdjustInfoToNoGpu();