Add fallback behavior if the last used profile cannot initialize

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index c496ffe34032dc98f91d26d70326ab24f6248eb8..b2596e4ce71b25927ba04444ad9c17f76dd10482 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -90,6 +90,7 @@
 #include "chrome/browser/ui/app_modal/chrome_javascript_native_dialog_factory.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/simple_message_box.h"
 #include "chrome/browser/ui/startup/bad_flags_prompt.h"
 #include "chrome/browser/ui/startup/default_browser_prompt.h"
 #include "chrome/browser/ui/startup/startup_browser_creator.h"
@@ -389,7 +390,7 @@ Profile* CreatePrimaryProfile(const content::MainFunctionParams& parameters,
     profile_list->Clear();
   }
 
-  Profile* profile = NULL;
+  Profile* profile = nullptr;
 #if defined(OS_CHROMEOS) || defined(OS_ANDROID)
   // On ChromeOS and Android the ProfileManager will use the same path as the
   // one we got passed. GetActiveUserProfile will therefore use the correct path
@@ -401,25 +402,91 @@ Profile* CreatePrimaryProfile(const content::MainFunctionParams& parameters,
   base::FilePath profile_path =
       GetStartupProfilePath(user_data_dir, parsed_command_line);
 
-  profile = g_browser_process->profile_manager()->GetProfile(
-      profile_path);
+  ProfileManager* profile_manager = g_browser_process->profile_manager();
+  profile = profile_manager->GetProfile(profile_path);
 
-  // If we're using the --new-profile-management flag and this profile is
-  // signed out, then we should show the user manager instead. By switching
-  // the active profile to the guest profile we ensure that no
-  // browser windows will be opened for the guest profile.
+  // If we're using the --new-profile-management flag and this profile is signed
+  // out, then we should show the user manager instead. By switching the active
+  // profile to the guest profile we ensure that no browser windows will be
+  // opened for the guest profile. The initialization of guest profile is
+  // possible to fail.
   if (switches::IsNewProfileManagement() &&
       profile &&
       !profile->IsGuestSession()) {
     ProfileAttributesEntry* entry;
-    bool has_entry = g_browser_process->profile_manager()->
-                         GetProfileAttributesStorage().
-                         GetProfileAttributesWithPath(profile_path, &entry);
+    bool has_entry = g_browser_process->profile_manager()
+                         ->GetProfileAttributesStorage()
+                         .GetProfileAttributesWithPath(profile_path, &entry);
     if (has_entry && entry->IsSigninRequired()) {
-      profile = g_browser_process->profile_manager()->GetProfile(
-          ProfileManager::GetGuestProfilePath());
+      profile = profile_manager->GetProfile(
+                                     ProfileManager::GetGuestProfilePath());
     }
   }
+
+  // If the user specified a profile and it fails to initialize, do not start
+  // chromium.
+  if (profiles::IsMultipleProfilesEnabled() &&
+      parsed_command_line.HasSwitch(switches::kProfileDirectory) &&
+      !profile) {
+    chrome::ShowWarningMessageBox(NULL,
+        base::UTF8ToUTF16("Unable to start chrome"),
+        base::UTF8ToUTF16("Cannot open or create the specified profile."));
+    return nullptr;

[WC Leung, 2016/06/06 20:01:36]

We need to get help from the UI team to determine the exact message in this
message box. Who should I contact?

Anyway, I know that I should not hard-code strings. Just want a confirmation
that a message box is the right UI be shown here before working on translatable
strings.

+  }
+
+  // If the last used profile is unable to initialize, see if any of other last
+  // opened profiles can initialize successfully. At this stage we assume
+  // creation of all new profile (including guest profile) to fail.
+  if (!profile) {
+    std::vector<Profile*> last_opened_profiles =
+        ProfileManager::GetLastOpenedProfiles();
+    // Get the first profile that is not signed out..
+    if (last_opened_profiles.size()) {
+      for (Profile* last_opened_profile : last_opened_profiles) {
+        ProfileAttributesEntry* entry;
+        bool has_entry =
+            g_browser_process->profile_manager()
+                             ->GetProfileAttributesStorage()
+                             .GetProfileAttributesWithPath(profile->GetPath(),
+                                                           &entry);
+        if (!has_entry || !entry->IsSigninRequired()) {
+          profile = last_opened_profile;
+          break;
+        }
+      }
+    }
+  }
+
+  // If it still fails, try to create a guest profile. Show the user manager
+  // if this is successful.
+  if (!profile) {
+    profile = profile_manager->GetProfile(
+                                   ProfileManager::GetGuestProfilePath());
+  }
+
+  // If still fails, try to open any non-signin profile.
+  if (!profile) {
+    std::vector<ProfileAttributesEntry*> entries =
+        profile_manager->GetProfileAttributesStorage()
+                       .GetAllProfilesAttributes();
+    for (ProfileAttributesEntry* entry : entries) {
+      if (!entry->IsSigninRequired()) {
+        profile = profile_manager->GetProfile(entry->GetPath());
+        if (profile)
+          break;
+      }
+    }
+  }
+
+  // If it continues to fail, we have to show an error message and give up.
+  if (!profile) {
+    chrome::ShowWarningMessageBox(NULL,
+        base::UTF8ToUTF16("Unable to start chrome"),
+        base::UTF8ToUTF16(
+            "Cannot load or create any profile in the user data directory.\n"
+            "The user data directory is possibly corrupted."));

[WC Leung, 2016/06/06 20:01:36]

Same for here. Anyway, should we also add some UMA histogram to log this error?
After the patch the crash is not there anymore, so we need some other kind of
logging.

If yes, then who is going to own the histogram(s)? (I'm not a Googler now, so it
sholudn't be me.)

+    return nullptr;
+  }
 #endif  // defined(OS_CHROMEOS) || defined(OS_ANDROID)
   if (profile) {
     UMA_HISTOGRAM_LONG_TIMES(
@@ -427,14 +494,12 @@ Profile* CreatePrimaryProfile(const content::MainFunctionParams& parameters,
     return profile;
   }
 
-#if !defined(OS_WIN)
   // TODO(port): fix this.  See comments near the definition of
   // user_data_dir.  It is better to CHECK-fail here than it is to
   // silently exit because of missing code in the above test.
   CHECK(profile) << "Cannot get default profile.";
-#endif  // !defined(OS_WIN)
 
-  return NULL;
+  return nullptr;
 }
 
 #if defined(OS_MACOSX)