[ios] Refactor SessionServiceIOS to remove dependency on BrowserState.

ios/chrome/browser/crash_report/crash_restore_helper_unittest.mm

Index: ios/chrome/browser/crash_report/crash_restore_helper_unittest.mm
diff --git a/ios/chrome/browser/crash_report/crash_restore_helper_unittest.mm b/ios/chrome/browser/crash_report/crash_restore_helper_unittest.mm
index 4eaf66f2b8a1be269beb7ac3e82d7fa23c9000de..a2297bdc45c5200645b368007e7cfb40b30b053e 100644
--- a/ios/chrome/browser/crash_report/crash_restore_helper_unittest.mm
+++ b/ios/chrome/browser/crash_report/crash_restore_helper_unittest.mm
@@ -56,15 +56,14 @@ TEST_F(CrashRestoreHelperTest, MoveAsideTest) {
 
   NSData* data = [NSData dataWithBytes:"hello" length:5];
   SessionServiceIOS* sessionService = [SessionServiceIOS sharedService];
-  NSString* profileStashPath =
+  NSString* statePath =
       base::SysUTF8ToNSString(chrome_browser_state_->GetStatePath().value());
-  NSString* sessionPath =
-      [sessionService sessionFilePathForDirectory:profileStashPath];
+  NSString* sessionPath = [sessionService sessionPathForDirectory:statePath];
   [fileManager createFileAtPath:sessionPath contents:data attributes:nil];
-  NSString* otrProfileStashPath = base::SysUTF8ToNSString(
+  NSString* otrStatePath = base::SysUTF8ToNSString(

[marq (ping after 24h), 2017/04/11 10:46:29]

Per crbug.com/3333, we prefer to just use 'incognito' instead of 'OTR'. 

(and, if not, we'd prefer offTheRecordStatePath to avoid the initialism).

[sdefresne, 2017/04/11 11:49:41]

Done.

       otr_chrome_browser_state_->GetStatePath().value());
   NSString* otrSessionPath =
-      [sessionService sessionFilePathForDirectory:otrProfileStashPath];
+      [sessionService sessionPathForDirectory:otrStatePath];
   [fileManager createFileAtPath:otrSessionPath contents:data attributes:nil];
 
   [helper_ moveAsideSessionInformation];