Don't crash by trying to set PageZoom on undead RenderWidgets

Web tests set page zoom on every RenderView's main frame, but some may
be holding a remote main frame. Don't try to set page zoom on those ones
and let the page zoom propagate from the main frame down to those
RenderViews and their child frames.

R=avi@chromium.org

Bug: 1006580
Change-Id: I411b9cd8d21f16e03649c9c716a3e6d1e7fc271e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1823317Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: danakj <danakj@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699963}

content/shell/test_runner/event_sender.cc

@@ -1818,22 +1818,37 @@ void EventSender::TextZoomOut() {
 
 void EventSender::ZoomPageIn() {
   for (WebViewTestProxy* view_proxy : interfaces()->GetWindowList()) {
-    view_proxy->GetWidget()->SetZoomLevelForTesting(
-        view_proxy->webview()->ZoomLevel() + 1);
+    // Only set page zoom on main frames. Any RenderViews that exist for
+    // a proxy main frame will hear about the change as a side effect of
+    // changing the main frame.
+    if (view_proxy->GetMainRenderFrame()) {
+      view_proxy->GetWidget()->SetZoomLevelForTesting(
+          view_proxy->webview()->ZoomLevel() + 1);
+    }
   }
 }
 
 void EventSender::ZoomPageOut() {
   for (WebViewTestProxy* view_proxy : interfaces()->GetWindowList()) {
-    view_proxy->GetWidget()->SetZoomLevelForTesting(
-        view_proxy->webview()->ZoomLevel() - 1);
+    // Only set page zoom on main frames. Any RenderViews that exist for
+    // a proxy main frame will hear about the change as a side effect of
+    // changing the main frame.
+    if (view_proxy->GetMainRenderFrame()) {
+      view_proxy->GetWidget()->SetZoomLevelForTesting(
+          view_proxy->webview()->ZoomLevel() - 1);
+    }
   }
 }
 
 void EventSender::SetPageZoomFactor(double zoom_factor) {
   for (WebViewTestProxy* view_proxy : interfaces()->GetWindowList()) {
-    view_proxy->GetWidget()->SetZoomLevelForTesting(std::log(zoom_factor) /
-                                                    std::log(1.2));
+    // Only set page zoom on main frames. Any RenderViews that exist for
+    // a proxy main frame will hear about the change as a side effect of
+    // changing the main frame.
+    if (view_proxy->GetMainRenderFrame()) {
+      view_proxy->GetWidget()->SetZoomLevelForTesting(std::log(zoom_factor) /
+                                                      std::log(1.2));
+    }
   }
 }