Remove now-unnecessary wrappers around gfx::Screen::GetScreen()

- ash::Shell::GetScreen()
- DisplayInfoProvider::GetActiveScreen()

Followup to https://codereview.chromium.org/1608733002/.

R=oshima@chromium.org, sky@chromium.org
BUG=558054

Review URL: https://codereview.chromium.org/1608053002

Cr-Commit-Position: refs/heads/master@{#371733}

3 files changed, 2 insertions, 10 deletions

diff --git a/extensions/browser/api/system_display/display_info_provider.h b/extensions/browser/api/system_display/display_info_provider.h
index e2fee24..1501e37 100644
--- a/extensions/browser/api/system_display/display_info_provider.h
+++ b/extensions/browser/api/system_display/display_info_provider.h
@@ -15,7 +15,6 @@
 
 namespace gfx {
 class Display;
-class Screen;
 }
 
 namespace extensions {
@@ -49,10 +48,6 @@ class DisplayInfoProvider {
                        const api::system_display::DisplayProperties& info,
                        std::string* error) = 0;
 
-  // Get the screen that is always active, which will be used for monitoring
-  // display changes events.
-  virtual gfx::Screen* GetActiveScreen() = 0;
-
   // Enable the unified desktop feature.
   virtual void EnableUnifiedDesktop(bool enable);
 
diff --git a/extensions/browser/api/system_display/system_display_apitest.cc b/extensions/browser/api/system_display/system_display_apitest.cc
index cdcb519..2c0548e 100644
--- a/extensions/browser/api/system_display/system_display_apitest.cc
+++ b/extensions/browser/api/system_display/system_display_apitest.cc
@@ -88,8 +88,6 @@ class MockDisplayInfoProvider : public DisplayInfoProvider {
     return true;
   }
 
-  gfx::Screen* GetActiveScreen() override { return NULL; }
-
   void EnableUnifiedDesktop(bool enable) override {
     unified_desktop_enabled_ = enable;
   }
diff --git a/extensions/browser/api/system_info/system_info_api.cc b/extensions/browser/api/system_info/system_info_api.cc
index 74181ca..42679d6 100644
--- a/extensions/browser/api/system_info/system_info_api.cc
+++ b/extensions/browser/api/system_info/system_info_api.cc
@@ -20,7 +20,6 @@
 #include "components/storage_monitor/storage_info.h"
 #include "components/storage_monitor/storage_monitor.h"
 #include "content/public/browser/browser_thread.h"
-#include "extensions/browser/api/system_display/display_info_provider.h"
 #include "extensions/browser/api/system_storage/storage_info_provider.h"
 #include "extensions/browser/extensions_browser_client.h"
 #include "extensions/common/api/system_display.h"
@@ -120,7 +119,7 @@ void SystemInfoEventRouter::AddEventListener(const std::string& event_name) {
     return;
 
   if (IsDisplayChangedEvent(event_name)) {
-    gfx::Screen* screen = DisplayInfoProvider::Get()->GetActiveScreen();
+    gfx::Screen* screen = gfx::Screen::GetScreen();
     if (screen)
       screen->AddObserver(this);
   }
@@ -146,7 +145,7 @@ void SystemInfoEventRouter::RemoveEventListener(const std::string& event_name) {
   }
 
   if (IsDisplayChangedEvent(event_name)) {
-    gfx::Screen* screen = DisplayInfoProvider::Get()->GetActiveScreen();
+    gfx::Screen* screen = gfx::Screen::GetScreen();
     if (screen)
       screen->RemoveObserver(this);
   }