HTTPS Previews: Add cmd line flags for the local blacklist

Adds flags to clear and add to the local blacklist. These flags are
evaluated on startup.

These flags are needed for Chrome Driver testing.

Bug: 908491
Change-Id: Id67f9393d826c9e6bd267eb8ac39dc1118a4bce7
Reviewed-on: https://chromium-review.googlesource.com/c/1351880Reviewed-by: Ryan Sturm <ryansturm@chromium.org>
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611809}

chrome/browser/previews/previews_lite_page_decider.cc

@@ -7,6 +7,7 @@
 #include <vector>
 
 #include "base/callback.h"
+#include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/rand_util.h"
 #include "base/time/default_tick_clock.h"
@@ -27,6 +28,7 @@
 #include "components/prefs/pref_service.h"
 #include "components/previews/content/previews_user_data.h"
 #include "components/previews/core/previews_experiments.h"
+#include "components/previews/core/previews_switches.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/navigation_handle.h"
@@ -142,13 +144,18 @@ PreviewsLitePageDecider::PreviewsLitePageDecider(
 
   DCHECK(!browser_context->IsOffTheRecord());
 
-  Profile* profile = Profile::FromBrowserContext(browser_context);
-  pref_service_ = profile->GetPrefs();
-  DCHECK(pref_service_);
-
+  pref_service_ = Profile::FromBrowserContext(browser_context)->GetPrefs();
   host_blacklist_ =
       pref_service_->GetDictionary(kHostBlacklist)->CreateDeepCopy();
 
+  // Note: This switch has no effect if |drp_settings| was null since
+  // |host_blacklist_| would be empty anyways.
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          previews::switches::kClearLitePageRedirectLocalBlacklist)) {
+    host_blacklist_->Clear();
+    pref_service_->Set(kHostBlacklist, *host_blacklist_);
+  }
+
   // Add |this| as an observer to DRP, but if DRP is already initialized, check
   // the prefs now.
   drp_settings_ = drp_settings;

components/previews/core/previews_switches.cc

@@ -17,5 +17,9 @@ const char kLitePageServerPreviewHost[] = "litepage-server-previews-host";
 const char kIgnoreLitePageRedirectOptimizationBlacklist[] =
     "ignore-litepage-redirect-optimization-blacklist";
 
+// Clears the local Lite Page Redirect blacklist on startup.
+const char kClearLitePageRedirectLocalBlacklist[] =
+    "clear-litepage-redirect-local-blacklist-on-startup";
+
 }  // namespace switches
 }  // namespace previews

components/previews/core/previews_switches.h

@@ -11,6 +11,7 @@ namespace switches {
 extern const char kIgnorePreviewsBlacklist[];
 extern const char kLitePageServerPreviewHost[];
 extern const char kIgnoreLitePageRedirectOptimizationBlacklist[];
+extern const char kClearLitePageRedirectLocalBlacklist[];
 
 }  // namespace switches
 }  // namespace previews