Make WebRtcWebcamBrowserTest fail faster.

chrome/browser/media/webrtc_browsertest_common.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/media/webrtc_browsertest_common.h"
 
 #include "base/files/file_util.h"
 #include "base/path_service.h"
+#include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/test/test_timeouts.h"
 #include "base/time/time.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_tabstrip.h"
 #include "chrome/common/chrome_paths.h"
 #include "content/public/test/browser_test_utils.h"
 
 namespace test {
 
@@ skipping 12 matching lines @@
 static const char kAdviseOnGclientSolution[] =
     "You need to add this solution to your .gclient to run this test:\n"
     "{\n"
     "  \"name\"        : \"webrtc.DEPS\",\n"
     "  \"url\"         : \"https://chromium.googlesource.com/chromium/deps/"
     "webrtc/webrtc.DEPS\",\n"
     "}";
 
 const int kDefaultPollIntervalMsec = 250;
 
+bool IsErrorResult(const std::string& result) {
+  return StartsWithASCII(result, "failed-", false);
+}
+
 base::FilePath GetReferenceFilesDir() {
   base::FilePath test_data_dir;
   PathService::Get(chrome::DIR_TEST_DATA, &test_data_dir);
 
   return test_data_dir.Append(kReferenceFilesDirName);
 }
 
 base::FilePath GetToolForPlatform(const std::string& tool_name) {
   base::FilePath tools_dir =
       GetReferenceFilesDir().Append(FILE_PATH_LITERAL("tools"));
@@ skipping 75 matching lines @@
   std::string result;
 
   while (base::Time::Now() - start_time < timeout) {
     std::string result;
     if (!content::ExecuteScriptAndExtractString(tab_contents, javascript,
                                                 &result)) {
       LOG(ERROR) << "Failed to execute javascript " << javascript;
       return false;
     }
 
-    if (evaluates_to == result)
+    if (evaluates_to == result) {
       return true;
+    } else if (IsErrorResult(result)) {
+      LOG(ERROR) << "|" << javascript << "| returned an error: " << result;
+      return false;
+    }
 
     // Sleep a bit here to keep this loop from spinlocking too badly.
     if (!SleepInJavascript(tab_contents, poll_interval_msec)) {
       // TODO(phoglund): Figure out why this fails every now and then.
       // It's not a huge deal if it does though.
       LOG(ERROR) << "Failed to sleep.";
     }
   }
   LOG(ERROR)
       << "Timed out while waiting for " << javascript
       << " to evaluate to " << evaluates_to << "; last result was '" << result
       << "'";
   return false;
 }
 
 }  // namespace test