Tweaks to the precache triggering code.

chrome/browser/android/precache/precache_launcher.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/precache/precache_launcher.h"
 
 #include <jni.h>
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_weak_ref.h"
@@ skipping 44 matching lines @@
 
 void PrecacheLauncher::Destroy(JNIEnv* env, jobject obj) {
   delete this;
 }
 
 void PrecacheLauncher::Start(JNIEnv* env, jobject obj) {
   // TODO(bengr): Add integration tests for the whole feature.
   Profile* profile = GetProfile();
 
   PrecacheManager* precache_manager = GetPrecacheManager(profile);
   history::HistoryService* hs = HistoryServiceFactory::GetForProfile(

[bengr, 2015/08/06 00:01:01]

nit: No need to get the hs if precache_manager is null.

[twifkak, 2015/08/06 00:18:17]

A future CL (not yet sent) moves the hs out of here entirely, so I'm not
inclined to worry about it.

       profile, ServiceAccessType::IMPLICIT_ACCESS);
 
-  if (precache_manager == nullptr || hs == nullptr ||
-      !precache_manager->IsPrecachingAllowed()) {
-    Java_PrecacheLauncher_onPrecacheCompletedCallback(
-        env, weak_java_precache_launcher_.get(env).obj());
+  if (precache_manager == nullptr || hs == nullptr) {
+    OnPrecacheCompleted();
     return;
   }
 
   precache_manager->StartPrecaching(
       base::Bind(&PrecacheLauncher::OnPrecacheCompleted,
                  weak_factory_.GetWeakPtr()),
       *hs);
 }
 
 void PrecacheLauncher::Cancel(JNIEnv* env, jobject obj) {
   Profile* profile = GetProfile();
   PrecacheManager* precache_manager = GetPrecacheManager(profile);
 
   precache_manager->CancelPrecaching();
 }
 
 void PrecacheLauncher::OnPrecacheCompleted() {
   JNIEnv* env = AttachCurrentThread();
   Java_PrecacheLauncher_onPrecacheCompletedCallback(
       env, weak_java_precache_launcher_.get(env).obj());
 }
 
 static jlong Init(JNIEnv* env, jobject obj) {
   return reinterpret_cast<intptr_t>(new PrecacheLauncher(env, obj));
 }
 
-static jboolean IsPrecachingEnabled(JNIEnv* env, jclass clazz) {
-  return PrecacheManager::IsPrecachingEnabled();
+// Must be run on the UI thread.
+static jboolean ShouldRun(JNIEnv* env, jobject obj) {
+  Profile* profile = GetProfile();
+  PrecacheManager* precache_manager = GetPrecacheManager(profile);
+  return precache_manager && precache_manager->ShouldRun();
 }
 
 bool RegisterPrecacheLauncher(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }