Make Linker.isUsed() static, and clean up the fallout.

content/shell/android/linker_test_apk/src/org/chromium/chromium_linker_test_apk/ChromiumLinkerTestActivity.java

 // Copyright 2014 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.
 
 package org.chromium.chromium_linker_test_apk;
 
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
@@ skipping 79 matching lines @@
         }
 
         if (!(hasModernLinkerSwitch || hasLegacyLinkerSwitch)) {
             Log.e(TAG, "Missing --use-linker command line argument.");
             finish();
         } else if (hasModernLinkerSwitch && hasLegacyLinkerSwitch) {
             Log.e(TAG, "Conflicting --use-linker command line arguments.");
             finish();
         }
 
-        // Set the requested Linker implementation from the command-line.
+        // Set the requested Linker implementation from the command-line, and
+        // register the test runner class by name.
         if (hasModernLinkerSwitch) {
-            Linker.setLinkerImplementationForTesting(Linker.LINKER_IMPLEMENTATION_MODERN);
+            Linker.setupForTesting(Linker.LINKER_IMPLEMENTATION_MODERN,
+                                   LinkerTests.class.getName());
         } else {
-            Linker.setLinkerImplementationForTesting(Linker.LINKER_IMPLEMENTATION_LEGACY);
+            Linker.setupForTesting(Linker.LINKER_IMPLEMENTATION_LEGACY,
+                                   LinkerTests.class.getName());
         }
 
         // Determine which kind of device to simulate from the command-line.
         int memoryDeviceConfig = Linker.MEMORY_DEVICE_CONFIG_NORMAL;
         if (hasLowMemoryDeviceSwitch) {
             memoryDeviceConfig = Linker.MEMORY_DEVICE_CONFIG_LOW;
         }
         Linker linker = Linker.getInstance();
         linker.setMemoryDeviceConfigForTesting(memoryDeviceConfig);
 
-        // Register the test runner class by name.
-        linker.setTestRunnerClassNameForTesting(LinkerTests.class.getName());
-
         // Load the library in the browser process, this will also run the test
         // runner in this process.
         try {
             LibraryLoader.get(LibraryProcessType.PROCESS_BROWSER)
                     .ensureInitialized(getApplicationContext());
         } catch (ProcessInitException e) {
             Log.i(TAG, "Cannot load chromium_linker_test:" +  e);
         }
 
         // Now, start a new renderer process by creating a new view.
@@ skipping 95 matching lines @@
         }
 
         Shell shell = mShellManager.getActiveShell();
         if (shell == null) {
             return null;
         }
 
         return shell.getContentViewCore();
     }
 }