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..45cb63e3b8ddf75472e436a6e1886e8fc73bed04 100644
--- a/chrome/browser/safe_browsing/srt_fetcher_win.cc
+++ b/chrome/browser/safe_browsing/srt_fetcher_win.cc
@@ -593,6 +593,10 @@ class SwReporterProcess : public base::RefCountedThreadSafe<SwReporterProcess> {
   // Starts a new instance of ChromePromptImpl to receive requests from the
   // reporter. Must be run on the IO thread.

[grt (UTC plus 2), 2017/04/21 11:10:58]

"...reporter and establishes the mojo connection to it." or somesuch

[ftirelo, 2017/04/24 15:47:46]

Done.

   void CreateChromePromptImpl(
+      base::ProcessHandle process,
+      mojo::edk::ConnectionParams connection_params,
+      std::unique_ptr<mojo::edk::PendingProcessConnection>
+          pending_process_connection,
       chrome_cleaner::mojom::ChromePromptRequest chrome_prompt_request);
 
   // Releases the instance of ChromePromptImpl. Must be run on the IO thread.
@@ -620,7 +624,7 @@ 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);
@@ -644,10 +648,12 @@ void SwReporterProcess::OnReporterDone() {
 base::Process SwReporterProcess::LaunchConnectedReporterProcess() {
   DCHECK(base::FeatureList::IsEnabled(kInBrowserCleanerUIFeature));
 
-  mojo::edk::PendingProcessConnection pending_process_connection;
+  std::unique_ptr<mojo::edk::PendingProcessConnection>
+      pending_process_connection =
+          base::MakeUnique<mojo::edk::PendingProcessConnection>();
   std::string mojo_pipe_token;
   mojo::ScopedMessagePipeHandle mojo_pipe =
-      pending_process_connection.CreateMessagePipe(&mojo_pipe_token);
+      pending_process_connection->CreateMessagePipe(&mojo_pipe_token);
   invocation_.command_line.AppendSwitchASCII(
       chrome_cleaner::kChromeMojoPipeTokenSwitch, mojo_pipe_token);
   invocation_.command_line.AppendSwitchASCII(
@@ -668,21 +674,19 @@ 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));
 
   // ChromePromptImpl tasks will need to run on the IO thread. There is no
   // need to synchronize its creation, since the client end will wait for this
   // initialization to be done before sending requests.
+  base::OnceClosure f = base::BindOnce(

[grt (UTC plus 2), 2017/04/21 11:10:59]

why introduce a local for this? if you really think it's cleaner, i think "auto"
is appropriate, and "f" must be replaced with something more clear as per "Names
should be descriptive; avoid abbreviation."
(https://google.github.io/styleguide/cppguide.html#General_Naming_Rules)

[ftirelo, 2017/04/24 15:47:46]

Left-over from a previous test; after it passed, I forgot to cleanup.  Thanks
for pointing it out.

+      &SwReporterProcess::CreateChromePromptImpl, base::RetainedRef(this),
+      reporter_process.Handle(),

[grt (UTC plus 2), 2017/04/21 11:10:58]

please document why it's safe to pass the naked handle value here. its validity
is bound by the lifetime of |reporter_process|.

[ftirelo, 2017/04/24 15:47:46]

Obsolete.

+      mojo::edk::ConnectionParams(channel.PassServerHandle()),
+      std::move(pending_process_connection), std::move(chrome_prompt_request));
   BrowserThread::GetTaskRunnerForThread(BrowserThread::IO)
-      ->PostTask(FROM_HERE,
-                 base::BindOnce(&SwReporterProcess::CreateChromePromptImpl,
-                                base::RetainedRef(this),
-                                std::move(chrome_prompt_request)));
+      ->PostTask(FROM_HERE, std::move(f));
 
   return reporter_process;
 }
@@ -696,12 +700,21 @@ base::Process SwReporterProcess::LaunchReporterProcess(
 }
 
 void SwReporterProcess::CreateChromePromptImpl(
+    base::ProcessHandle process,
+    mojo::edk::ConnectionParams connection_params,
+    std::unique_ptr<mojo::edk::PendingProcessConnection>
+        pending_process_connection,
     chrome_cleaner::mojom::ChromePromptRequest chrome_prompt_request) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(base::FeatureList::IsEnabled(kInBrowserCleanerUIFeature));
 
   chrome_prompt_impl_ =
       base::MakeUnique<ChromePromptImpl>(std::move(chrome_prompt_request));

[grt (UTC plus 2), 2017/04/21 11:10:58]

perhaps this could call a function on the testing delegate to create the CPI so
that a test can override methods on it.

[ftirelo, 2017/04/24 15:47:46]

Done.

+
+  pending_process_connection->Connect(
+      process, std::move(connection_params),
+      base::Bind(&ChromePromptImpl::OnConnectionError,
+                 base::Unretained(chrome_prompt_impl_.get())));

[grt (UTC plus 2), 2017/04/21 11:10:58]

please document why this Unretained is safe. is it impossible for a connection
error to be posted and waiting to run while a previously-posted task deletes
this SwReporterProcess?

[ftirelo, 2017/04/24 15:47:46]

Obsolete.

 }
 
 void SwReporterProcess::ReleaseChromePromptImpl() {
@@ -934,7 +947,7 @@ 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 +967,7 @@ 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();