Revert "Ensure test settings are fully reset between tests"

This reverts commit c92df469.

Reason for revert: This CL caused test failures in https://ci.chromium.org/p/chromium/builders/ci/WebKit%20Linux%20Leak/16175

Original change's description:
> Ensure test settings are fully reset between tests
> 
> Javascript can run after BlinkTestRunner::OnResetRendererAfterWebTest,
> dirtying TestRunner state for the next test. A navigation to about:blank
> is done after every test. This patch resets the TestRunner state after
> the navigation to about:blank, when we are sure no test javascript can
> change TestRunner state. This fixes a class of flaky bugs.
> 
> This behavior happened with video-overlay-scroll.html which would set a
> custom layout dump (setCustomTextOutput) in a fullscreenchange event
> handler. This event handler was not removed at the end of the test
> (this will be fixed in a followup), and would run a second time, after
> the custom text output setting was reset. This caused later tests to
> run with custom text output from video-overlay-scroll.html. With this
> patch, video-scrolled-iframe.html is no longer flaky.
> 
> Code in WebFrameTestProxy::BeginNavigation to intercept navigations
> relied on TestRunner::PolicyDelegateEnabled being reset before it ran.
> This patch now skips WebFrameTestProxy::BeginNavigation when the test
> is not running.
> 
> Bug: 1048597
> Change-Id: I888f7cc2ae91d7d3cfdd143a7573f62cb052c1cc
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2275348
> Reviewed-by: danakj <danakj@chromium.org>
> Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
> Commit-Queue: Philip Rogers <pdr@chromium.org>
> Auto-Submit: Philip Rogers <pdr@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#784110}

TBR=danakj@chromium.org,wangxianzhu@chromium.org,pdr@chromium.org

Change-Id: Ieb22e1d115bd284aaa942c60ca7c6dc5e8ea71b6
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1048597
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2276418Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Commit-Queue: Christian Dullweber <dullweber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#784367}

content/shell/renderer/web_test/blink_test_runner.cc

@@ -465,7 +465,6 @@ void BlinkTestRunner::DidCommitNavigationInMainFrame() {
     return;
 
   waiting_for_reset_navigation_to_about_blank_ = false;
-  web_view_test_proxy_->test_interfaces()->ResetAll();
   GetWebTestControlHostRemote()->ResetRendererAfterWebTestDone();
 }
 
@@ -554,10 +553,8 @@ void BlinkTestRunner::OnResetRendererAfterWebTest() {
   // BlinkTestMsg_Reset should always be sent to the *current* view.
   DCHECK(web_view_test_proxy_->GetMainRenderFrame());
 
-  // Instead of resetting for the next test here, delay until after the
-  // navigation to about:blank (this is in |DidCommitNavigationInMainFrame()|).
-  // This ensures we reset settings that are set between now and the load of
-  // about:blank.
+  TestInterfaces* interfaces = web_view_test_proxy_->test_interfaces();
+  interfaces->ResetAll();
 
   // Navigating to about:blank will make sure that no new loads are initiated
   // by the renderer.

content/shell/renderer/web_test/web_frame_test_proxy.cc

@@ -478,13 +478,6 @@ void WebFrameTestProxy::WillSendRequest(blink::WebURLRequest& request) {
 
 void WebFrameTestProxy::BeginNavigation(
     std::unique_ptr<blink::WebNavigationInfo> info) {
-  // This check for whether the test is running ensures we do not intercept
-  // the about:blank navigation between tests.
-  if (!test_runner()->TestIsRunning()) {
-    RenderFrameImpl::BeginNavigation(std::move(info));
-    return;
-  }
-
   if (test_runner()->ShouldDumpNavigationPolicy()) {
     blink_test_runner()->PrintMessage(
         "Default policy for navigation to '" +