Adds error handling support for the SwReporter launcher.

chrome/browser/safe_browsing/srt_fetcher_win.cc

Index: chrome/browser/safe_browsing/srt_fetcher_win.cc
diff --git a/chrome/browser/safe_browsing/srt_fetcher_win.cc b/chrome/browser/safe_browsing/srt_fetcher_win.cc
index 6f2ee0f88e9f5b90d245d708ba646f5d6e69535e..801ab0400b9b19f275884dfff74098a3416b277d 100644
--- a/chrome/browser/safe_browsing/srt_fetcher_win.cc
+++ b/chrome/browser/safe_browsing/srt_fetcher_win.cc
@@ -545,6 +545,20 @@ void DisplaySRTPrompt(const base::FilePath& download_path) {
     global_error->ShowBubbleView(browser);
 }
 
+// Handles the case when the remote end has been closed, by performing the
+// necessary cleanups if the prompt dialog is being shown to the user.
+void OnConnectionClosed() {
+  // Placeholder. This should handle cases when the reporter process is
+  // disconnected (e.g. due to a crash) and the prompt dialog is being shown
+  // to the user.
+}
+
+// Handles the case when a mojo::ReportBadMessage has been explicitly reported.
+void OnConnectionError(const std::string& message) {
+  // Placeholder. This should handle cases when the reporter process sends
+  // a bad message and the prompt dialog is being shown to the user.
+}
+
 // Class responsible for launching the reporter process and waiting for its
 // completion. If feature InBrowserCleanerUI is enabled, this object will also
 // be responsible for starting the ChromePromptImpl object on the IO thread and
@@ -591,7 +605,8 @@ class SwReporterProcess : public base::RefCountedThreadSafe<SwReporterProcess> {
   base::Process LaunchConnectedReporterProcess();
 
   // Starts a new instance of ChromePromptImpl to receive requests from the
-  // reporter. Must be run on the IO thread.
+  // reporter and establishes the mojo connection to it.
+  // Must be run on the IO thread.
   void CreateChromePromptImpl(
       chrome_cleaner::mojom::ChromePromptRequest chrome_prompt_request);
 
@@ -620,7 +635,7 @@ int SwReporterProcess::LaunchAndWaitForExitOnBackgroundThread() {
 
   // This exit code is used to identify that a reporter run didn't happen, so
   // the result should be ignored and a rerun scheduled for the usual delay.
-  int exit_code = kReporterFailureExitCode;
+  int exit_code = kReporterNotLaunchedExitCode;
   UMAHistogramReporter uma(invocation_.suffix);
   if (reporter_process.IsValid()) {
     uma.RecordReporterStep(SW_REPORTER_START_EXECUTION);
@@ -668,10 +683,6 @@ base::Process SwReporterProcess::LaunchConnectedReporterProcess() {
   if (!reporter_process.IsValid())
     return reporter_process;
 
-  pending_process_connection.Connect(
-      reporter_process.Handle(),
-      mojo::edk::ConnectionParams(channel.PassServerHandle()));
-
   chrome_cleaner::mojom::ChromePromptRequest chrome_prompt_request;
   chrome_prompt_request.Bind(std::move(mojo_pipe));
 
@@ -684,6 +695,16 @@ base::Process SwReporterProcess::LaunchConnectedReporterProcess() {
                                 base::RetainedRef(this),
                                 std::move(chrome_prompt_request)));
 
+  mojo::edk::ProcessErrorCallback on_connection_error =
+      g_testing_delegate_
+          ? base::Bind(&SwReporterTestingDelegate::OnConnectionError,
+                       base::Unretained(g_testing_delegate_))
+          : base::Bind(&OnConnectionError);
+  pending_process_connection.Connect(
+      reporter_process.Handle(),
+      mojo::edk::ConnectionParams(channel.PassServerHandle()),
+      on_connection_error);
+
   return reporter_process;
 }
 
@@ -701,7 +722,11 @@ void SwReporterProcess::CreateChromePromptImpl(
   DCHECK(base::FeatureList::IsEnabled(kInBrowserCleanerUIFeature));
 
   chrome_prompt_impl_ =
-      base::MakeUnique<ChromePromptImpl>(std::move(chrome_prompt_request));
+      g_testing_delegate_
+          ? g_testing_delegate_->CreateChromePromptImpl(
+                std::move(chrome_prompt_request))
+          : base::MakeUnique<ChromePromptImpl>(std::move(chrome_prompt_request),
+                                               base::Bind(&OnConnectionClosed));
 }
 
 void SwReporterProcess::ReleaseChromePromptImpl() {
@@ -934,7 +959,7 @@ class ReporterRunner : public chrome::BrowserListObserver {
     base::TimeDelta reporter_running_time = now - reporter_start_time;
 
     // Don't continue the current queue of reporters if one failed to launch.
-    if (exit_code == kReporterFailureExitCode)
+    if (exit_code == kReporterNotLaunchedExitCode)
       current_invocations_ = SwReporterQueue();
 
     // As soon as we're not running this queue, schedule the next overall queue
@@ -954,7 +979,7 @@ class ReporterRunner : public chrome::BrowserListObserver {
     // code itself doesn't need to be logged in this case because
     // SW_REPORTER_FAILED_TO_START is logged in
     // |LaunchAndWaitForExitOnBackgroundThread|.)
-    if (exit_code == kReporterFailureExitCode)
+    if (exit_code == kReporterNotLaunchedExitCode)
       return;
 
     const auto& finished_invocation = sw_reporter_process->invocation();