Add setting to isolate zoom changes by default.

chrome/browser/profiles/host_zoom_map_browsertest.cc

Index: chrome/browser/profiles/host_zoom_map_browsertest.cc
diff --git a/chrome/browser/profiles/host_zoom_map_browsertest.cc b/chrome/browser/profiles/host_zoom_map_browsertest.cc
index afb92bb131e8332329d7ff6e9729c954b3e7def4..3ec5812af695d36d87433c3d5c03dc91bbb1672f 100644
--- a/chrome/browser/profiles/host_zoom_map_browsertest.cc
+++ b/chrome/browser/profiles/host_zoom_map_browsertest.cc
@@ -37,6 +37,9 @@
 #include "components/zoom/page_zoom.h"
 #include "components/zoom/zoom_event_manager.h"
 #include "content/public/browser/host_zoom_map.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
 #include "content/public/test/test_utils.h"
 #include "net/dns/mock_host_resolver.h"
 #include "net/test/embedded_test_server/embedded_test_server.h"
@@ -416,3 +419,40 @@ IN_PROC_BROWSER_TEST_F(HostZoomMapBrowserTest, PageScaleIsOneChanged) {
   observer.BlockUntilZoomLevelForHostHasChanged(test_host);
   EXPECT_TRUE(content::HostZoomMap::PageScaleFactorIsOne(web_contents));
 }
+
+// Test to make sure that temporary zoom levels can be copied to
+// new views.
+IN_PROC_BROWSER_TEST_F(HostZoomMapBrowserTest,
+                       PreserveTemporaryZoomLevelFrom) {
+  ui_test_utils::NavigateToURL(browser(), GURL(url::kAboutBlankURL));
+  content::WebContents* old_web_contents =
+      browser()->tab_strip_model()->GetActiveWebContents();
+  HostZoomMap* old_host_zoom_map =
+      HostZoomMap::GetForWebContents(old_web_contents);
+  content::RenderViewHost* old_view_host =
+      old_web_contents->GetMainFrame()->GetRenderViewHost();
+
+  double temp_zoom_level = old_host_zoom_map->GetDefaultZoomLevel() + 1.0;
+
+  old_host_zoom_map->SetTemporaryZoomLevel(
+      old_view_host->GetProcess()->GetID(), old_view_host->GetRoutingID(),
+      temp_zoom_level);
+
+  ui_test_utils::NavigateToURLWithDisposition(
+      browser(), GURL(url::kAboutBlankURL),
+      WindowOpenDisposition::NEW_FOREGROUND_TAB,
+      ui_test_utils::BROWSER_TEST_WAIT_FOR_NAVIGATION);
+  content::WebContents* new_web_contents =
+      browser()->tab_strip_model()->GetActiveWebContents();
+  ASSERT_NE(old_web_contents, new_web_contents);
+  HostZoomMap* new_host_zoom_map =
+      HostZoomMap::GetForWebContents(new_web_contents);
+
+  ASSERT_FALSE(content::ZoomValuesEqual(
+      temp_zoom_level, HostZoomMap::GetZoomLevel(new_web_contents)));
+  new_host_zoom_map->PreserveTemporaryZoomLevelFrom(
+      old_host_zoom_map, old_web_contents->GetMainFrame(),
+      new_web_contents->GetMainFrame());
+  EXPECT_TRUE(content::ZoomValuesEqual(
+      temp_zoom_level, HostZoomMap::GetZoomLevel(new_web_contents)));
+}