Retry browser startup in desktop_browser_finder.

telemetry/telemetry/internal/backends/chrome/desktop_browser_finder.py

Index: telemetry/telemetry/internal/backends/chrome/desktop_browser_finder.py
diff --git a/telemetry/telemetry/internal/backends/chrome/desktop_browser_finder.py b/telemetry/telemetry/internal/backends/chrome/desktop_browser_finder.py
index e2cedb744857bbd6886669a9f69166f38ed0d018..d8f68d8f819283b3197ff62b91b217f52dab8019 100644
--- a/telemetry/telemetry/internal/backends/chrome/desktop_browser_finder.py
+++ b/telemetry/telemetry/internal/backends/chrome/desktop_browser_finder.py
@@ -60,12 +60,37 @@ class PossibleDesktopBrowser(possible_browser.PossibleBrowser):
 
     self._InitPlatformIfNeeded()
 
-    browser_backend = desktop_browser_backend.DesktopBrowserBackend(
-        self._platform_backend,
-        finder_options.browser_options, self._local_executable,
-        self._flash_path, self._is_content_shell, self._browser_directory)
-    return browser.Browser(
-        browser_backend, self._platform_backend, self._credentials_path)
+    num_retries = 3
+    for x in range(0, num_retries):
+      returned_browser = None
+      try:
+        returned_browser = None
+
+        browser_backend = desktop_browser_backend.DesktopBrowserBackend(
+            self._platform_backend,
+            finder_options.browser_options, self._local_executable,
+            self._flash_path, self._is_content_shell, self._browser_directory)
+
+        returned_browser = browser.Browser(
+            browser_backend, self._platform_backend, self._credentials_path)
+
+        # Try fetching the zeroth tab. If this works, then the browser
+        # appears to be working.
+        _ = returned_browser.tabs[0]

[Ken Russell (switch to Gerrit), 2017/05/08 21:22:02]

The fetching of the zeroth tab is causing
DevToolsClientBackendTest.testGetUpdatedInspectableContexts to fail. Even if
this tab is fetched and then immediately closed, this test still fails.

I'm removing this part of the CL. It looks like it still detects whether the
browser came up successfully.

+
+        return returned_browser
+      except Exception:
+        logging.warning('Browser creation failed (attempt %d of %d), retrying' %
+                        ((x + 1), num_retries))
+        # Attempt to clean up things left over from the failed browser startup.
+        try:
+          if returned_browser:
+            returned_browser.Close()
+        except Exception:
+          pass
+        # Re-raise the exception the last time through.
+        if x == num_retries - 1:
+          raise
 
   def SupportsOptions(self, browser_options):
     if ((len(browser_options.extensions_to_load) != 0)