Disabling tests that are frequently, almost-consistently failing on CrOS

This CL disables the following tests on CrOS:
- RenderFrameHostImplBrowserTest.VisibilityScrolledOutOfView
- SignedExchangeRequestHandlerBrowserTest.Simple
- SignedExchangeRequestHandlerBrowserTest.VariantMatch

Bug: 1016865, 954217
Change-Id: Ifa0bc6652c581bcfbc524931121975dedf9807fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1873889
Commit-Queue: Łukasz Anforowicz <lukasza@chromium.org>
Commit-Queue: Alex Moshchuk <alexmos@chromium.org>
Auto-Submit: Łukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: Alex Moshchuk <alexmos@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708337}

content/browser/frame_host/render_frame_host_impl_browsertest.cc

@@ -2117,6 +2117,12 @@ IN_PROC_BROWSER_TEST_F(RenderFrameHostImplBrowserTest,
   EXPECT_EQ(0, process->get_media_stream_count_for_testing());
 }
 
+#if defined(OS_CHROMEOS)
+// ChromeOS failures are tracked in https://crbug.com/954217
+#define MAYBE_VisibilityScrolledOutOfView DISABLED_VisibilityScrolledOutOfView
+#else
+#define MAYBE_VisibilityScrolledOutOfView VisibilityScrolledOutOfView
+#endif
 // Test that a frame is visible/hidden depending on its WebContents visibility
 // state.
 IN_PROC_BROWSER_TEST_F(RenderFrameHostImplBrowserTest,

content/browser/web_package/signed_exchange_request_handler_browsertest.cc

@@ -281,6 +281,13 @@ class SignedExchangeRequestHandlerBrowserTest
 };
 
 IN_PROC_BROWSER_TEST_P(SignedExchangeRequestHandlerBrowserTest, Simple) {
+#if defined(OS_CHROMEOS)
+  // https://crbug.com/1016865 tracks the test failures on CrOS that are only
+  // happening in the mode special-cased below.
+  if (UsePrefetch() && SXGPrefetchCacheIsEnabled())
+    return;
+#endif
+
   InstallMockCert();
   InstallMockCertChainInterceptor();
 
@@ -355,6 +362,13 @@ IN_PROC_BROWSER_TEST_P(SignedExchangeRequestHandlerBrowserTest, Simple) {
 }
 
 IN_PROC_BROWSER_TEST_P(SignedExchangeRequestHandlerBrowserTest, VariantMatch) {
+#if defined(OS_CHROMEOS)
+  // https://crbug.com/1016865 tracks the test failures on CrOS that are only
+  // happening in the mode special-cased below.
+  if (UsePrefetch() && SXGPrefetchCacheIsEnabled())
+    return;
+#endif
+
   if (!SetAcceptLangs("en-US,fr"))
     return;
   InstallUrlInterceptor(