Don't share renderers between unrelated tabs on Android.

content/browser/site_instance_impl_unittest.cc

 // Copyright (c) 2012 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 "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_vector.h"
 #include "base/strings/string16.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/browsing_instance.h"
@@ skipping 544 matching lines @@
 }
 
 // Test to ensure that pages that require certain privileges are grouped
 // in processes with similar pages.
 TEST_F(SiteInstanceTest, ProcessSharingByType) {
   // This test shouldn't run with --site-per-process mode, since it doesn't
   // allow render process reuse, which this test explicitly exercises.
   if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kSitePerProcess))
     return;
 
+  // On Android by default the number of renderer hosts is unlimited and process
+  // sharing doesn't happen. We set the override so that the test can run
+  // everywhere.
+  RenderProcessHost::SetMaxRendererProcessCount(kMaxRendererProcessCount);
+
   ChildProcessSecurityPolicyImpl* policy =
       ChildProcessSecurityPolicyImpl::GetInstance();
 
   // Make a bunch of mock renderers so that we hit the limit.
   scoped_ptr<TestBrowserContext> browser_context(new TestBrowserContext());
   ScopedVector<MockRenderProcessHost> hosts;
   for (size_t i = 0; i < kMaxRendererProcessCount; ++i)
     hosts.push_back(new MockRenderProcessHost(browser_context.get()));
 
   // Create some extension instances and make sure they share a process.
@@ skipping 25 matching lines @@
 
   // Make sure none of differing privilege processes are mixed.
   EXPECT_NE(extension1_instance->GetProcess(), webui1_instance->GetProcess());
 
   for (size_t i = 0; i < kMaxRendererProcessCount; ++i) {
     EXPECT_NE(extension1_instance->GetProcess(), hosts[i]);
     EXPECT_NE(webui1_instance->GetProcess(), hosts[i]);
   }
 
   DrainMessageLoops();
+
+  // Disable the process limit override.
+  RenderProcessHost::SetMaxRendererProcessCount(0u);
 }
 
 // Test to ensure that HasWrongProcessForURL behaves properly for different
 // types of URLs.
 TEST_F(SiteInstanceTest, HasWrongProcessForURL) {
   scoped_ptr<TestBrowserContext> browser_context(new TestBrowserContext());
   scoped_ptr<RenderProcessHost> host;
   scoped_refptr<SiteInstanceImpl> instance(static_cast<SiteInstanceImpl*>(
       SiteInstance::Create(browser_context.get())));
 
@@ skipping 137 matching lines @@
   EXPECT_TRUE(instance->GetSiteURL().is_empty());
   host.reset(instance->GetProcess());
 
   EXPECT_FALSE(RenderProcessHostImpl::GetProcessHostForSite(
       browser_context.get(), GURL()));
 
   DrainMessageLoops();
 }
 
 }  // namespace content