[ios] Moves classes named TestWebState into anonymous namespaces.

Multiple test files were defined classes named TestWebState in the
global namespace, which is an ODR violations and was causing crashes in
ios_chrome_unittests. Since these are all test-specific helpers, this CL
moves them into anonymous namespaces.

BUG=None

Change-Id: If9ca07916e8d0a5063bb45abe3f971f58c224150
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2335336Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794236}

ios/chrome/browser/crash_report/crash_reporter_url_observer_unittest.mm

@@ -23,6 +23,8 @@
 #error "This file requires ARC support."
 #endif
 
+namespace {
+
 class TestWebState : public web::TestWebState {
  public:
   void LoadURL(const GURL& url) {
@@ -53,6 +55,8 @@ class TestWebState : public web::TestWebState {
   std::unique_ptr<web::NavigationItem> pending_item_;
 };
 
+}  // namespace
+
 @interface DictionaryParameterSetter : NSObject <CrashReporterParameterSetter>
 @property(nonatomic) NSMutableDictionary* params;
 @end

ios/chrome/browser/reading_list/reading_list_web_state_observer_unittest.mm

@@ -26,7 +26,6 @@ const char kTestURL[] = "http://foo.bar";
 const char kTestTitle[] = "title";
 const char kTestDistilledPath[] = "distilled/page.html";
 const char kTestDistilledURL[] = "http://foo.bar/distilled";
-}
 
 // A Test navigation manager that checks if Reload was called.
 class TestNavigationManager : public web::TestNavigationManager {
@@ -60,6 +59,8 @@ class TestWebState : public web::TestWebState {
   GURL last_opened_url_;
 };
 
+}  // namespace
+
 // Test fixture to test loading of Reading list entries.
 class ReadingListWebStateObserverTest : public web::WebTest {
  public:

ios/components/security_interstitials/lookalikes/lookalike_url_blocking_page_unittest.mm

@@ -33,6 +33,7 @@ using base::test::ios::WaitUntilConditionOrTimeout;
 using base::test::ios::kSpinDelaySeconds;
 
 namespace {
+
 // Constants used for testing metrics.
 const char kInterstitialDecisionMetric[] = "interstitial.lookalike.decision";
 const char kInterstitialInteractionMetric[] =
@@ -53,7 +54,6 @@ std::unique_ptr<LookalikeUrlBlockingPage> CreateBlockingPage(
       std::make_unique<LookalikeUrlControllerClient>(web_state, safe_url,
                                                      request_url, "en-US"));
 }
-}  // namespace
 
 // A Test web state that sets the visible URL to the last opened URL.
 class TestWebState : public web::TestWebState {
@@ -63,6 +63,8 @@ class TestWebState : public web::TestWebState {
   }
 };
 
+}  // namespace
+
 // Test fixture for SafeBrowsingBlockingPage.
 class LookalikeUrlBlockingPageTest : public PlatformTest {
  public: