Exit GPU process to fallback to SwiftShader cleanly on Linux

There is no clean way to shut down GLX, so it's best to fail GPU
process launch. In GpuProcessHost::DidFailInitialize(), we will
fallback to the next mode, which is SwiftShader, right away.

BUG=971169
TEST=manual
R=piman@chromium.org

Change-Id: I615c2a9a956b081f48dbbfa1d7ba4768dd363f4d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1707986
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Cr-Commit-Position: refs/heads/master@{#678944}

content/test/gpu/gpu_tests/gpu_process_integration_test.py

@@ -302,19 +302,22 @@ class GpuProcessIntegrationTest(gpu_integration_test.GpuIntegrationTest):
           return
       else:
         pass
-    feature_status_for_hardware_gpu_list = self.tab.EvaluateJavaScript(
-        'browserBridge.gpuInfo.featureStatusForHardwareGpu.featureStatus')
-    for name, status in feature_status_for_hardware_gpu_list.items():
-      if name == 'webgl':
-        if status != 'unavailable_off':
-          self.fail('WebGL status for hardware GPU failed: %s' % status)
-          return
-      elif name == '2d_canvas':
-        if status != 'enabled':
-          self.fail('2D Canvas status for hardware GPU failed: %s' % status)
-          return
-      else:
-        pass
+    if not sys.platform.startswith('linux'):
+      # On Linux we relaunch GPU process to fallback to SwiftShader, therefore
+      # featureStatusForHardwareGpu isn't available.
+      feature_status_for_hardware_gpu_list = self.tab.EvaluateJavaScript(
+          'browserBridge.gpuInfo.featureStatusForHardwareGpu.featureStatus')
+      for name, status in feature_status_for_hardware_gpu_list.items():
+        if name == 'webgl':
+          if status != 'unavailable_off':
+            self.fail('WebGL status for hardware GPU failed: %s' % status)
+            return
+        elif name == '2d_canvas':
+          if status != 'enabled':
+            self.fail('2D Canvas status for hardware GPU failed: %s' % status)
+            return
+        else:
+          pass
 
   def _GpuProcess_one_extra_workaround(self, test_path):
     # Start this test by launching the browser with no command line

gpu/ipc/service/gpu_init.cc

@@ -284,8 +284,14 @@ bool GpuInit::InitializeAndStartSandbox(base::CommandLine* command_line,
   }
   if (gl_initialized && use_swiftshader &&
       gl::GetGLImplementation() != gl::kGLImplementationSwiftShaderGL) {
+#if defined(OS_LINUX)
+    VLOG(1) << "Quit GPU process launch to fallback to SwiftShader cleanly "
+            << "on Linux";
+    return false;
+#else
     gl::init::ShutdownGL(true);
     gl_initialized = false;
+#endif  // OS_LINUX
   }
   if (!gl_initialized)
     gl_initialized = gl::init::InitializeGLNoExtensionsOneOff();
@@ -311,12 +317,18 @@ bool GpuInit::InitializeAndStartSandbox(base::CommandLine* command_line,
         command_line, gpu_feature_info_,
         gpu_preferences_.disable_software_rasterizer, false);
     if (use_swiftshader) {
+#if defined(OS_LINUX)
+      VLOG(1) << "Quit GPU process launch to fallback to SwiftShader cleanly "
+              << "on Linux";
+      return false;
+#else
       gl::init::ShutdownGL(true);
       if (!gl::init::InitializeGLNoExtensionsOneOff()) {
         VLOG(1) << "gl::init::InitializeGLNoExtensionsOneOff with SwiftShader "
                 << "failed";
         return false;
       }
+#endif  // OS_LINUX
     }
   }
 
@@ -359,12 +371,9 @@ bool GpuInit::InitializeAndStartSandbox(base::CommandLine* command_line,
         command_line, gpu_feature_info_,
         gpu_preferences_.disable_software_rasterizer, false);
     if (use_swiftshader) {
-      gl::init::ShutdownGL(true);
-      if (!gl::init::InitializeGLNoExtensionsOneOff()) {
-        VLOG(1) << "gl::init::InitializeGLNoExtensionsOneOff with SwiftShader "
-                << "failed";
-        return false;
-      }
+      VLOG(1) << "Quit GPU process launch to fallback to SwiftShader cleanly "
+              << "on Linux";
+      return false;
     }
   }
 #endif  // defined(OS_LINUX)