HTTPS Previews: Add cmd line flag to ignore opt hints blacklist

This is needed for ChromeDriver testing. See bug.

Bug: 908491
Change-Id: Ifaf1505757badc0b9c39b2a98e48a733a26564d7
Reviewed-on: https://chromium-review.googlesource.com/c/1351097Reviewed-by: Doug Arnett <dougarnett@chromium.org>
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611738}

components/previews/content/previews_hints.cc

@@ -7,6 +7,7 @@
 #include <array>
 #include <string>
 
+#include "base/command_line.h"
 #include "base/files/file.h"
 #include "base/files/file_util.h"
 #include "base/metrics/field_trial_params.h"
@@ -18,6 +19,7 @@
 #include "components/optimization_guide/url_pattern_with_wildcards.h"
 #include "components/previews/core/bloom_filter.h"
 #include "components/previews/core/previews_features.h"
+#include "components/previews/core/previews_switches.h"
 #include "url/gurl.h"
 
 namespace previews {
@@ -615,6 +617,11 @@ bool PreviewsHints::IsBlacklisted(const GURL& url, PreviewsType type) const {
   // Check large scale blacklists received from the server.
   // (At some point, we may have blacklisting to check in HintCache as well.)
   if (type == PreviewsType::LITE_PAGE_REDIRECT) {
+    if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+            switches::kIgnoreLitePageRedirectOptimizationBlacklist)) {
+      return false;
+    }
+
     if (lite_page_redirect_blacklist_)
       return lite_page_redirect_blacklist_->ContainsHostSuffix(url);
   }

components/previews/content/previews_hints_unittest.cc

@@ -4,12 +4,14 @@
 
 #include "components/previews/content/previews_hints.h"
 
+#include "base/command_line.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/test/metrics/histogram_tester.h"
 #include "base/test/scoped_feature_list.h"
 #include "components/optimization_guide/optimization_guide_service_observer.h"
 #include "components/optimization_guide/proto/hints.pb.h"
 #include "components/previews/core/previews_features.h"
+#include "components/previews/core/previews_switches.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
@@ -178,6 +180,22 @@ TEST_F(PreviewsHintsTest, IsBlacklisted) {
                                              PreviewsType::LITE_PAGE_REDIRECT));
 }
 
+TEST_F(PreviewsHintsTest, IgnoreLitePageRedirectBlacklist) {
+  std::unique_ptr<PreviewsHints> previews_hints =
+      PreviewsHints::CreateForTesting(
+          std::make_unique<TestHostFilter>("black.com"));
+
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kIgnoreLitePageRedirectOptimizationBlacklist);
+
+  EXPECT_FALSE(previews_hints->IsBlacklisted(GURL("https://black.com/path"),
+                                             PreviewsType::LOFI));
+  EXPECT_FALSE(previews_hints->IsBlacklisted(GURL("https://black.com/path"),
+                                             PreviewsType::LITE_PAGE_REDIRECT));
+  EXPECT_FALSE(previews_hints->IsBlacklisted(GURL("https://nonblack.com"),
+                                             PreviewsType::LITE_PAGE_REDIRECT));
+}
+
 TEST_F(PreviewsHintsTest, IsBlacklistedFromConfig) {
   base::test::ScopedFeatureList scoped_list;
   scoped_list.InitAndEnableFeature(features::kLitePageServerPreviews);

components/previews/core/previews_switches.cc

@@ -13,5 +13,9 @@ const char kIgnorePreviewsBlacklist[] = "ignore-previews-blacklist";
 // Override the Lite Page Preview Host.
 const char kLitePageServerPreviewHost[] = "litepage-server-previews-host";
 
+// Ignore the optimization hints blacklist for Lite Page Redirect previews.
+const char kIgnoreLitePageRedirectOptimizationBlacklist[] =
+    "ignore-litepage-redirect-optimization-blacklist";
+
 }  // namespace switches
 }  // namespace previews

components/previews/core/previews_switches.h

@@ -10,6 +10,7 @@ namespace switches {
 
 extern const char kIgnorePreviewsBlacklist[];
 extern const char kLitePageServerPreviewHost[];
+extern const char kIgnoreLitePageRedirectOptimizationBlacklist[];
 
 }  // namespace switches
 }  // namespace previews