Suppress service manager log spam

Suppresses log spam about "native service" failures when the service in
question is content_renderer. This is because, unlike for any other
service in the system, hitting the native service launcher codepath for
content_renderer is simply an innocuous side effect of some raciness
between browser features and renderer termination.

Bug: None
Change-Id: I8f73c7ecbe167c160e9df0f3aac3214063997d39
Reviewed-on: https://chromium-review.googlesource.com/1103155Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Ken Rockot <rockot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567873}

content/browser/service_manager/service_manager_context.cc

@@ -245,8 +245,20 @@ class NullServiceProcessLauncherFactory
  private:
   std::unique_ptr<service_manager::ServiceProcessLauncher> Create(
       const base::FilePath& service_path) override {
-    LOG(ERROR) << "Attempting to run unsupported native service: "
-               << service_path.value();
+    // There are innocuous races where browser code may attempt to connect
+    // to a specific renderer instance through the Service Manager after that
+    // renderer has been terminated. These result in this code path being hit
+    // fairly regularly and the resulting log spam causes confusion. We suppress
+    // this message only for "content_renderer".
+    const base::FilePath::StringType kRendererServiceFilename =
+        base::FilePath().AppendASCII(mojom::kRendererServiceName).value();
+    const base::FilePath::StringType service_executable =
+        service_path.BaseName().value();
+    if (service_executable.find(kRendererServiceFilename) ==
+        base::FilePath::StringType::npos) {
+      LOG(ERROR) << "Attempting to run unsupported native service: "
+                 << service_path.value();
+    }
     return nullptr;
   }