[Cleanup] Use WebContentsConsoleObserver in RFHImpl tests

Update RenderFrameHostImpl browser tests to use
WebContentsConsoleObserver instead of ConsoleObserverDelegate. This
allows us to observe console messages added without overriding the
existing delegate of the WebContents.
Bonus cleanups:
- Avoids the static_cast to WebContentsImpl
- No need for a filter specifying "*"

Bug: 1034150
Change-Id: I24513a79cbcce736cb003cb4fba3c966db9fcd19
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1976293Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#727272}

content/browser/frame_host/render_frame_host_impl_browsertest.cc

@@ -2662,10 +2662,7 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostImplBrowserTest,
   base::test::ScopedFeatureList feature_list;
   feature_list.InitAndEnableFeature(features::kCookieDeprecationMessages);
 
-  WebContentsImpl* web_contents =
-      static_cast<WebContentsImpl*>(shell()->web_contents());
-  ConsoleObserverDelegate console_observer(web_contents, "*");
-  web_contents->SetDelegate(&console_observer);
+  WebContentsConsoleObserver console_observer(shell()->web_contents());
 
   // Test deprecation messages for SameSiteByDefault.
   // Set a cookie without SameSite on b.com, then access it in a cross-site
@@ -2691,7 +2688,8 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostImplBrowserTest,
   // Another copy of the message appears because we have navigated.
   EXPECT_TRUE(NavigateToURL(shell(), url));
   EXPECT_EQ(3u, console_observer.messages().size());
-  EXPECT_EQ(console_observer.messages()[1], console_observer.messages()[2]);
+  EXPECT_EQ(console_observer.messages()[1].message,
+            console_observer.messages()[2].message);
 }
 
 // Enable SameSiteByDefaultCookies to test deprecation messages for
@@ -2712,10 +2710,7 @@ class RenderFrameHostImplSameSiteByDefaultCookiesBrowserTest
 
 IN_PROC_BROWSER_TEST_F(RenderFrameHostImplSameSiteByDefaultCookiesBrowserTest,
                        DisplaySameSiteCookieDeprecationMessages) {
-  WebContentsImpl* web_contents =
-      static_cast<WebContentsImpl*>(shell()->web_contents());
-  ConsoleObserverDelegate console_observer(web_contents, "*");
-  web_contents->SetDelegate(&console_observer);
+  WebContentsConsoleObserver console_observer(shell()->web_contents());
 
   // Test deprecation messages for SameSiteByDefault.
   // Set a cookie without SameSite on b.com, then access it in a cross-site
@@ -2755,9 +2750,12 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostImplSameSiteByDefaultCookiesBrowserTest,
   EXPECT_EQ(3u, console_observer.messages().size());
 
   // Check that the messages were all distinct.
-  EXPECT_NE(console_observer.messages()[0], console_observer.messages()[1]);
-  EXPECT_NE(console_observer.messages()[0], console_observer.messages()[2]);
-  EXPECT_NE(console_observer.messages()[1], console_observer.messages()[2]);
+  EXPECT_NE(console_observer.messages()[0].message,
+            console_observer.messages()[1].message);
+  EXPECT_NE(console_observer.messages()[0].message,
+            console_observer.messages()[2].message);
+  EXPECT_NE(console_observer.messages()[1].message,
+            console_observer.messages()[2].message);
 }
 
 // Test that the SameSite-by-default console warnings are not emitted
@@ -2765,10 +2763,7 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostImplSameSiteByDefaultCookiesBrowserTest,
 // Regression test for https://crbug.com/1027318.
 IN_PROC_BROWSER_TEST_F(RenderFrameHostImplSameSiteByDefaultCookiesBrowserTest,
                        NoMessagesIfCookieWouldBeRejectedForOtherReasons) {
-  WebContentsImpl* web_contents =
-      static_cast<WebContentsImpl*>(shell()->web_contents());
-  ConsoleObserverDelegate console_observer(web_contents, "*");
-  web_contents->SetDelegate(&console_observer);
+  WebContentsConsoleObserver console_observer(shell()->web_contents());
 
   GURL url = embedded_test_server()->GetURL(
       "x.com", "/set-cookie?cookiewithpath=1;path=/set-cookie");