Zoom Extension API (chrome)

chrome/browser/ui/zoom/zoom_controller.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 "chrome/browser/ui/zoom/zoom_controller.h"
 
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_finder.h"
+#include "chrome/browser/ui/zoom/zoom_event_manager.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/page_zoom.h"
 #include "grit/theme_resources.h"
 #include "net/base/net_util.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(ZoomController);
 
 ZoomController::ZoomController(content::WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
-      zoom_percent_(100),
+      zoom_mode_(kZoomModeDefault),
       observer_(NULL),
       browser_context_(web_contents->GetBrowserContext()) {
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
-  default_zoom_level_.Init(prefs::kDefaultZoomLevel, profile->GetPrefs(),
-                           base::Bind(&ZoomController::UpdateState,
-                                      base::Unretained(this),
-                                      std::string()));
+  default_zoom_level_.Init(
+      prefs::kDefaultZoomLevel, profile->GetPrefs(),
+      base::Bind(static_cast<void(ZoomController::*)(

[Devlin, 2014/06/16 19:04:49]

Is this all just because you added the other method with the shadowing bool? 
Why not just make that one have a different name, rather than put this in?

[wjmaclean, 2014/06/18 19:03:55]

Done.

+          const std::string&)>(&ZoomController::UpdateState),
+                 base::Unretained(this),
+                 std::string()));
+  zoom_level_ = default_zoom_level_.GetValue();
 
   zoom_subscription_ = content::HostZoomMap::GetForBrowserContext(
       browser_context_)->AddZoomLevelChangedCallback(
           base::Bind(&ZoomController::OnZoomLevelChanged,
                      base::Unretained(this)));
 
   UpdateState(std::string());
 }
 
 ZoomController::~ZoomController() {}
 
 bool ZoomController::IsAtDefaultZoom() const {
-  return content::ZoomValuesEqual(
-      content::HostZoomMap::GetZoomLevel(web_contents()),
-      default_zoom_level_.GetValue());
+  return content::ZoomValuesEqual(GetZoomLevel(),
+                                  default_zoom_level_.GetValue());
 }
 
 int ZoomController::GetResourceForZoomLevel() const {
   if (IsAtDefaultZoom())
     return IDR_ZOOM_NORMAL;
-  double zoom = content::HostZoomMap::GetZoomLevel(web_contents());
+  double zoom = GetZoomLevel();
   return zoom > default_zoom_level_.GetValue() ? IDR_ZOOM_PLUS : IDR_ZOOM_MINUS;

[Devlin, 2014/06/16 19:04:50]

nit: inline double zoom's value.

[wjmaclean, 2014/06/18 19:03:54]

Done.

Let me know if this is what you were looking for here.

 }
 
+const extensions::Extension* ZoomController::last_extension() const {

[Devlin, 2014/06/16 19:04:49]

why not defined in the header?

[wjmaclean, 2014/06/18 19:03:55]

Done.

+  return last_extension_.get();
+}
+
+double ZoomController::GetZoomLevel() const {
+  if (zoom_mode_ == kZoomModeManual)
+    return zoom_level_;
+  else
+    return content::HostZoomMap::GetZoomLevel(web_contents());
+}
+
+int ZoomController::GetZoomPercent() const {
+  double zoom_factor = content::ZoomLevelToZoomFactor(GetZoomLevel());
+  return static_cast<int>(zoom_factor * 100 + 0.5);
+}
+
+bool ZoomController::SetZoomLevel(double zoom_level) {
+  scoped_refptr<const extensions::Extension> null_extension_pointer;
+  // An extension did not initiate this zoom change.
+  return SetZoomLevelByExtension(zoom_level, null_extension_pointer);
+}
+
+bool ZoomController::SetZoomLevelByExtension(
+    double zoom_level,
+    scoped_refptr<const extensions::Extension> extension) {
+  // Cannot zoom in disabled mode.
+  if (zoom_mode_ == kZoomModeDisabled)
+    return false;
+
+  if (zoom_mode_ == kZoomModeManual) {
+    double old_zoom_level = zoom_level_;
+    zoom_level_ = zoom_level;
+
+    // TODO(wjmaclean) Do we care about filling in host/scheme here?
+    content::HostZoomMap::ZoomLevelChange change;
+    change.mode = content::HostZoomMap::ZOOM_CHANGED_TEMPORARY_ZOOM;
+    change.zoom_level = zoom_level;
+    ZoomEventManager::GetForBrowserContext(web_contents()->GetBrowserContext())
+        ->OnZoomLevelChanged(change);
+
+    observer_->OnZoomChangeInitiated(
+        web_contents(), old_zoom_level, zoom_level, zoom_mode_);
+
+    return true;
+  }
+
+  // Store extension data so that |extension| can be attributed when the zoom
+  // change completes..

[Devlin, 2014/06/16 19:04:50]

Either 1 '.' or 3.  Not two. :)

[wjmaclean, 2014/06/18 19:03:54]

Done.

+  extensions_.push(extension.get());
+
+  // Do not actually rescale the page in manual mode.
+  content::HostZoomMap* zoom_map = content::HostZoomMap::GetForBrowserContext(
+      web_contents()->GetBrowserContext());
+  DCHECK(zoom_map);
+  double old_zoom_level = GetZoomLevel();
+  int render_process_id = web_contents()->GetRenderProcessHost()->GetID();
+  int render_view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
+  if (zoom_mode_ == kZoomModeIsolated ||
+      zoom_map->UsesTemporaryZoomLevel(render_process_id, render_view_id)) {
+    zoom_map->SetTemporaryZoomLevel(
+        render_process_id, render_view_id, zoom_level);
+  } else {
+    // TODO(wjmaclean) If there is no entry, do we really want to proceed? If
+    // not, then we shouldn't have pushed the extension above, nor should we
+    // notify the observer below. Re-write this before submitting.

[Devlin, 2014/06/16 19:04:49]

Address this.

[wjmaclean, 2014/06/18 19:03:55]

Done.

+    content::NavigationEntry* entry =
+        web_contents()->GetController().GetLastCommittedEntry();
+    std::string host =
+        net::GetHostOrSpecFromURL(entry ? entry->GetURL() : GURL::EmptyGURL());
+    zoom_map->SetZoomLevelForHost(host, zoom_level);
+  }
+  observer_->OnZoomChangeInitiated(
+      web_contents(), old_zoom_level, zoom_level, zoom_mode_);
+
+  return true;
+}
+
+void ZoomController::SetZoomMode(ZoomMode new_mode) {
+  if (new_mode == zoom_mode_)
+    return;
+
+  content::HostZoomMap* zoom_map = content::HostZoomMap::GetForBrowserContext(
+      web_contents()->GetBrowserContext());
+  DCHECK(zoom_map);
+  int render_process_id = web_contents()->GetRenderProcessHost()->GetID();
+  int render_view_id = web_contents()->GetRenderViewHost()->GetRoutingID();
+  double original_zoom_level = GetZoomLevel();
+
+  switch (new_mode) {
+    case kZoomModeDefault: {
+      content::NavigationEntry* entry =
+          web_contents()->GetController().GetLastCommittedEntry();
+      GURL url;
+      if (entry)
+        url = entry->GetURL();
+      std::string host = net::GetHostOrSpecFromURL(url);
+
+      if (zoom_map->HasZoomLevel(url.scheme(), host)) {
+        // All the other modes are per-tab, but setting this mode shouldn't
+        // affect the zoom level of other tabs; if there are other tabs with
+        // the same origin, then set this tab's zoom level to match theirs.
+        // TODO(wjmaclean) How to convert this call?

[Devlin, 2014/06/16 19:04:49]

Address this.

[wjmaclean, 2014/06/18 19:03:55]

Done.

I'm not sure what I had in mind when I wrote this TODO, but the code as it
stands seems ok. I did clean up the comment a bit.

+        double origin_zoom_level =
+            zoom_map->GetZoomLevelForHostAndScheme(url.scheme(), host);
+        zoom_map->SetTemporaryZoomLevel(
+            render_process_id, render_view_id, origin_zoom_level);
+      } else {
+        // The host will need a level prior to removing the temporary level.
+        zoom_map->SetZoomLevelForHost(host, original_zoom_level);
+      }
+      // Remove per-tab zoom data for this tab.
+      zoom_map->ClearTemporaryZoomLevel(render_process_id, render_view_id);
+      break;
+    }
+    case kZoomModeIsolated: {
+      // Unless the zoom mode was |kZoomModeDisabled| before this call, the page
+      // needs an initial isolated zoom back to the same level it was at in the
+      // other mode.
+      if (zoom_mode_ != kZoomModeDisabled) {
+        zoom_map->SetTemporaryZoomLevel(
+            render_process_id, render_view_id, original_zoom_level);
+      }
+      break;
+    }
+    case kZoomModeManual: {
+      // Unless the zoom mode was |kZoomModeDisabled| before this call, the page
+      // needs to be resized to the default zoom before calling SetZoomLevel()
+      // so that the page can be resized manually to the same zoom as before.
+      if (zoom_mode_ != kZoomModeDisabled) {
+        zoom_map->SetTemporaryZoomLevel(render_process_id, render_view_id, 0);
+        zoom_level_ = original_zoom_level;
+      }
+      break;
+    }
+    case kZoomModeDisabled: {
+      // The page needs to be zoomed back to default before disabling the zoom
+      zoom_map->SetTemporaryZoomLevel(render_process_id, render_view_id, 0);
+      break;
+    }
+  }
+
+  zoom_mode_ = new_mode;
+}
+
 void ZoomController::DidNavigateMainFrame(
     const content::LoadCommittedDetails& details,
     const content::FrameNavigateParams& params) {
   // If the main frame's content has changed, the new page may have a different
   // zoom level from the old one.
   UpdateState(std::string());
 }
 
 void ZoomController::OnZoomLevelChanged(
     const content::HostZoomMap::ZoomLevelChange& change) {
-  UpdateState(change.host);
+  UpdateState(change.host,
+              change.mode == content::HostZoomMap::ZOOM_CHANGED_TEMPORARY_ZOOM);
 }
 
 void ZoomController::UpdateState(const std::string& host) {
+  UpdateState(host, false);
+}
+
+void ZoomController::UpdateState(const std::string& host,
+                                 bool is_temporary_zoom) {
+  // Update |last_extension_|.
+  if (!extensions_.empty()) {

[Devlin, 2014/06/16 19:04:50]

This seems odd for a few reasons.

1.  If we are certain that the last extension to make a request is the last to
update the state, why not set last_extension() when the call was made?
2.  extensions_ can be full of NULLs (above).
3.  UpdateState() will be called every time we navigate a page - but should we
really be setting last_extension_ in that case?  It seems more like this should
only happen in OnZoomLevelChanged...

[wjmaclean, 2014/06/18 19:03:54]

Agreed, the code as it stands in this CL is convoluted and confusing. I have
re-thought it and simplified it considerably.

+    last_extension_ = extensions_.front().get();
+    extensions_.pop();
+  }
+
   // If |host| is empty, all observers should be updated.
   if (!host.empty()) {
     // Use the navigation entry's URL instead of the WebContents' so virtual
     // URLs work (e.g. chrome://settings). http://crbug.com/153950
     content::NavigationEntry* entry =
         web_contents()->GetController().GetLastCommittedEntry();
     if (!entry ||
         host != net::GetHostOrSpecFromURL(entry->GetURL())) {
       return;
     }
   }
 
-  bool dummy;
-  zoom_percent_ = web_contents()->GetZoomPercent(&dummy, &dummy);
+  if (observer_) {
+    // The zoom bubble can be shown for all normal, per-origin zoom changes
+    // (where the host will not be empty and the zoom is not temporary), or any
+    // special zoom changes (where the zoom mode will not be "default").
+    bool can_show_bubble =
+        zoom_mode_ != kZoomModeDefault ||
+        (!host.empty() && !is_temporary_zoom);
+    observer_->OnZoomChanged(web_contents(), can_show_bubble);
+  }
 
-  if (observer_)
-    observer_->OnZoomChanged(web_contents(), !host.empty());
+  last_extension_ = NULL;
 }
+
+void ZoomController::ZoomCallback(

[Devlin, 2014/06/16 19:04:50]

When is this used?

[wjmaclean, 2014/06/18 19:03:54]

Removed.

+    scoped_refptr<const extensions::Extension> extension,
+    const base::Callback<void(void)>& callback) {
+  extensions_.push(extension);
+  callback.Run();
+}