Control distillability with command-line flag

BUG=646384

Review-Url: https://codereview.chromium.org/2361643004
Cr-Commit-Position: refs/heads/master@{#420617}

chrome/browser/chrome_content_browser_client.cc

@@ -1617,6 +1617,11 @@ void ChromeContentBrowserClient::AppendExtraCommandLineSwitches(
     MaybeAppendBlinkSettingsSwitchForFieldTrial(
         browser_command_line, command_line);
 
+#if defined(OS_ANDROID)
+    // If the platform is Android, force the distillability service on.
+    command_line->AppendSwitch(switches::kEnableDistillabilityService);
+#endif
+
     // Please keep this in alphabetical order.
     static const char* const kSwitchNames[] = {
 #if defined(OS_ANDROID)
@@ -1648,6 +1653,7 @@ void ChromeContentBrowserClient::AppendExtraCommandLineSwitches(
       switches::kDisableJavaScriptHarmonyShipping,
       switches::kDisableNewBookmarkApps,
       switches::kEnableBenchmarking,
+      switches::kEnableDistillabilityService,
       switches::kEnableNaCl,
 #if !defined(DISABLE_NACL)
       switches::kEnableNaClDebug,

chrome/browser/dom_distiller/distillable_page_utils_browsertest.cc

@@ -96,6 +96,7 @@ class DistillablePageUtilsBrowserTestOption : public InProcessBrowserTest {
     command_line->AppendSwitch(switches::kEnableDomDistiller);
     command_line->AppendSwitchASCII(switches::kReaderModeHeuristics,
         Option);
+    command_line->AppendSwitch(switches::kEnableDistillabilityService);
   }
 
   void SetUpOnMainThread() override {

chrome/renderer/chrome_content_renderer_client.cc

@@ -69,6 +69,7 @@
 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_headers.h"
 #include "components/dom_distiller/content/renderer/distillability_agent.h"
 #include "components/dom_distiller/content/renderer/distiller_js_render_frame_observer.h"
+#include "components/dom_distiller/core/dom_distiller_switches.h"
 #include "components/dom_distiller/core/url_constants.h"
 #include "components/error_page/common/localized_error.h"
 #include "components/network_hints/renderer/prescient_networking_dispatcher.h"
@@ -510,9 +511,12 @@ void ChromeContentRendererClient::RenderFrameCreated(
   new dom_distiller::DistillerJsRenderFrameObserver(
       render_frame, chrome::ISOLATED_WORLD_ID_CHROME_INTERNAL);
 
-  // Create DistillabilityAgent to send distillability updates to
-  // DistillabilityDriver in the browser process.
-  new dom_distiller::DistillabilityAgent(render_frame);
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  if (command_line->HasSwitch(switches::kEnableDistillabilityService)) {
+    // Create DistillabilityAgent to send distillability updates to
+    // DistillabilityDriver in the browser process.
+    new dom_distiller::DistillabilityAgent(render_frame);
+  }
 
   // Set up a mojo service to test if this page is a contextual search page.
   new contextual_search::OverlayJsRenderFrameObserver(render_frame);

components/dom_distiller/core/dom_distiller_switches.cc

@@ -6,6 +6,7 @@
 
 namespace switches {
 
+const char kEnableDistillabilityService[] = "enable-distillability-service";
 const char kEnableDomDistiller[] = "enable-dom-distiller";
 const char kEnableSyncArticles[] = "enable-sync-articles";
 const char kReaderModeHeuristics[] = "reader-mode-heuristics";

components/dom_distiller/core/dom_distiller_switches.h

@@ -10,6 +10,9 @@
 
 namespace switches {
 
+// Switch to enable the distillability service on the renderer.
+extern const char kEnableDistillabilityService[];
+
 // Switch to enable the DOM distiller.
 extern const char kEnableDomDistiller[];