Zoom level limits must be set before setting a zoom level.

content/renderer/render_view_browsertest.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/basictypes.h"
 
 #include "base/shared_memory.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "content/common/intents_messages.h"
@@ skipping 1680 matching lines @@
   ASSERT_EQ(utf16_length, bounds.size());
   for (size_t i = 0; i < utf16_length; ++i) {
     if (is_surrogate_pair_empty_rect[i]) {
       EXPECT_EQ(0, bounds[i].width());
     } else {
       EXPECT_LT(0, bounds[i].width());
     }
   }
   view()->OnImeConfirmComposition(empty_string, ui::Range::InvalidRange());
 }
+
+TEST_F(RenderViewImplTest, ZoomLimit) {

[darin (slow to review), 2012/08/06 20:44:16]

it is not clear to me how this test would have caught the bug.  can you please
explain to me how it works?

[kinaba, 2012/08/06 23:39:23]

See the inline comments below.

+  const double kMinZoomLevel =
+      WebKit::WebView::zoomFactorToZoomLevel(content::kMinimumZoomFactor);
+  const double kMaxZoomLevel =
+      WebKit::WebView::zoomFactorToZoomLevel(content::kMaximumZoomFactor);
+
+  ViewMsg_Navigate_Params params;
+  params.page_id = -1;
+  params.navigation_type = ViewMsg_Navigate_Type::NORMAL;
+
+  params.url = GURL("data:text/html,min_zoomlimit_test");

[kinaba, 2012/08/06 23:39:23]

Here, RenderViewImpl stores zoom level setting (25%) for this url.

+  view()->OnSetZoomLevelForLoadingURL(params.url, kMinZoomLevel);

[kinaba, 2012/08/06 23:39:23]

Navigate to the URL. UndateURL is called and the stored zoom level (25%) is
loaded. What happened before this patch is:
1. webview()->setZoomLevel(0.25) is called
2. 25% is rounded up to 50% (because by  default WebView::minTextSizeMultiplier
= 0.5 is set as the limit in WebView).
http://trac.webkit.org/browser/trunk/Source/WebKit/chromium/src/WebViewImpl.c...
3. webview()->zoomLimitsChanged(0.25, 5.0) is called.

After this patch:
1. webview()->zoomLimitsChanged(0.25, 5.0) is called.
2. webview()->setZoomLevel(0.25) is called.
3. 25% is 25%. Because lower bound is already changed to 0.25.

+  view()->OnNavigate(params);
+  ProcessPendingMessages();
+  EXPECT_DOUBLE_EQ(kMinZoomLevel, view()->GetWebView()->zoomLevel());
+
+  params.url = GURL("data:text/html,max_zoomlimit_test");
+  view()->OnSetZoomLevelForLoadingURL(params.url, kMaxZoomLevel);
+  view()->OnNavigate(params);
+  ProcessPendingMessages();
+  EXPECT_DOUBLE_EQ(kMaxZoomLevel, view()->GetWebView()->zoomLevel());

[kinaba, 2012/08/06 23:39:23]

Ah, this "max" level part does not trigger the bug because the 5.0 upper bound
is already set above. I'll soon add some line for it to do some meaningful
test...

+}