Add a WebLayer API to prewarm a spare renderer process.

Bug: 1114946
Change-Id: Id73c5537ab2de1912af57e3235e88adcdb52016c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2343770
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Darin Fisher <darin@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797754}

weblayer/browser/java/org/chromium/weblayer_private/ProfileImpl.java

@@ -199,6 +199,13 @@ public final class ProfileImpl extends IProfile.Stub implements BrowserContextHa
         ProfileImplJni.get().removeBrowserPersistenceStorage(mNativeProfile, ids, baseCallback);
     }
 
+    @Override
+    public void prepareForPossibleCrossOriginNavigation() {
+        StrictModeWorkaround.apply();
+        checkNotDestroyed();
+        ProfileImplJni.get().prepareForPossibleCrossOriginNavigation(mNativeProfile);
+    }
+
     void checkNotDestroyed() {
         if (!mBeingDeleted) return;
         throw new IllegalArgumentException("Profile being destroyed: " + mName);
@@ -266,5 +273,6 @@ public final class ProfileImpl extends IProfile.Stub implements BrowserContextHa
         void getBrowserPersistenceIds(long nativeProfileImpl, Callback<String[]> callback);
         void removeBrowserPersistenceStorage(
                 long nativeProfileImpl, String[] ids, Callback<Boolean> callback);
+        void prepareForPossibleCrossOriginNavigation(long nativeProfileImpl);
     }
 }

weblayer/browser/java/org/chromium/weblayer_private/interfaces/IProfile.aidl

@@ -35,4 +35,5 @@ interface IProfile {
   void getBrowserPersistenceIds(in IObjectWrapper resultCallback) = 9;
   void removeBrowserPersistenceStorage(in String[] ids,
                                        in IObjectWrapper resultCallback) = 10;
+  void prepareForPossibleCrossOriginNavigation() = 11;
 }

weblayer/browser/profile_impl.cc

@@ -26,6 +26,7 @@
 #include "content/public/browser/browsing_data_remover.h"
 #include "content/public/browser/device_service.h"
 #include "content/public/browser/download_manager.h"
+#include "content/public/browser/render_process_host.h"
 #include "content/public/browser/storage_partition.h"
 #include "services/network/public/mojom/network_context.mojom.h"
 #include "weblayer/browser/android/metrics/weblayer_metrics_service_client.h"
@@ -544,6 +545,10 @@ void ProfileImpl::RemoveBrowserPersistenceStorage(
       base::flat_set<std::string>(ids.begin(), ids.end()));
 }
 
+void ProfileImpl::PrepareForPossibleCrossOriginNavigation(JNIEnv* env) {
+  PrepareForPossibleCrossOriginNavigation();
+}
+
 #endif  // OS_ANDROID
 
 base::FilePath ProfileImpl::GetBrowserPersisterDataBaseDir() const {
@@ -627,6 +632,10 @@ void ProfileImpl::GetCachedFaviconForPageUrl(
                                 &cancelable_task_tracker_);
 }
 
+void ProfileImpl::PrepareForPossibleCrossOriginNavigation() {
+  content::RenderProcessHost::WarmupSpareRenderProcessHost(GetBrowserContext());
+}
+
 int ProfileImpl::GetNumberOfBrowsers() {
   const auto& browsers = BrowserList::GetInstance()->browsers();
   return std::count_if(browsers.begin(), browsers.end(),

weblayer/browser/profile_impl.h

@@ -94,6 +94,7 @@ class ProfileImpl : public Profile {
   void GetCachedFaviconForPageUrl(
       const GURL& page_url,
       base::OnceCallback<void(gfx::Image)> callback) override;
+  void PrepareForPossibleCrossOriginNavigation() override;
 
 #if defined(OS_ANDROID)
   ProfileImpl(JNIEnv* env,
@@ -125,6 +126,7 @@ class ProfileImpl : public Profile {
       JNIEnv* env,
       const base::android::JavaRef<jobjectArray>& j_ids,
       const base::android::JavaRef<jobject>& j_callback);
+  void PrepareForPossibleCrossOriginNavigation(JNIEnv* env);
 #endif
 
   const base::FilePath& download_directory() { return download_directory_; }

weblayer/public/java/org/chromium/weblayer/Profile.java

@@ -313,6 +313,30 @@ public class Profile {
         }
     }
 
+    /**
+     * If an embedder knows that a cross-origin navigation is likely starting soon they can call
+     * this method to start a spare renderer process. A subsequent navigation may use this
+     * preinitialized process, improving performance.
+     *
+     * It is safe to call this multiple times or when it is not certain that the spare renderer will
+     * be used, although calling this too eagerly may reduce performance as unnecessary processes
+     * are created.
+     *
+     * @since 85
+     */
+    public void prepareForPossibleCrossOriginNavigation() {
+        ThreadCheck.ensureOnUiThread();
+        if (WebLayer.getSupportedMajorVersionInternal() < 85) {
+            throw new UnsupportedOperationException();
+        }
+
+        try {
+            mImpl.prepareForPossibleCrossOriginNavigation();
+        } catch (RemoteException e) {
+            throw new APICallException(e);
+        }
+    }
+
     static final class DownloadCallbackClientImpl extends IDownloadCallbackClient.Stub {
         private final DownloadCallback mCallback;
 

weblayer/public/profile.h

@@ -102,6 +102,15 @@ class Profile {
   virtual void GetCachedFaviconForPageUrl(
       const GURL& page_url,
       base::OnceCallback<void(gfx::Image)> callback) = 0;
+
+  // If an embedder knows that a cross-origin navigation is likely starting soon
+  // they can call this method to start a spare renderer process. A subsequent
+  // navigation may use this preinitialized process, improving performance.
+
+  // It is safe to call this multiple times or when it is not certain that the
+  // spare renderer will be used, although calling this too eagerly may reduce
+  // performance as unnecessary processes are created.
+  virtual void PrepareForPossibleCrossOriginNavigation() = 0;
 };
 
 }  // namespace weblayer