Update //base to chromium 9659b08ea5a34f889dc4166217f438095ddc10d2

base/android/java/src/org/chromium/base/library_loader/Linker.java

Index: base/android/java/src/org/chromium/base/library_loader/Linker.java
diff --git a/base/android/java/src/org/chromium/base/library_loader/Linker.java b/base/android/java/src/org/chromium/base/library_loader/Linker.java
index 9a64a3fddbfd3b9837326daa6aaabc9edbdceb22..c769339620df9bae97d72735f05b030d064bb57a 100644
--- a/base/android/java/src/org/chromium/base/library_loader/Linker.java
+++ b/base/android/java/src/org/chromium/base/library_loader/Linker.java
@@ -1,4 +1,4 @@
-// Copyright 2014 The Chromium Authors. All rights reserved.
+// Copyright 2015 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.
 
@@ -8,14 +8,10 @@ import android.os.Bundle;
 import android.os.Parcel;
 import android.os.ParcelFileDescriptor;
 import android.os.Parcelable;
-import android.util.Log;
 
-import org.chromium.base.CalledByNative;
-import org.chromium.base.SysUtils;
-import org.chromium.base.ThreadUtils;
+import org.chromium.base.Log;
 import org.chromium.base.annotations.AccessedByNative;
 
-import java.io.FileNotFoundException;
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
@@ -153,13 +149,19 @@ import javax.annotation.Nullable;
  *
  *    This method also ensures the process uses the shared RELROs.
  */
-public class Linker {
-
-    // Log tag for this class. This must match the name of the linker's native library.
-    private static final String TAG = "chromium_android_linker";
+public abstract class Linker {
+    // Log tag for this class.
+    private static final String TAG = "cr.library_loader";
 
     // Set to true to enable debug logs.
-    private static final boolean DEBUG = false;
+    protected static final boolean DEBUG = false;
+
+    // Used to pass the shared RELRO Bundle through Binder.
+    public static final String EXTRA_LINKER_SHARED_RELROS =
+            "org.chromium.base.android.linker.shared_relros";
+
+    // Guards all access to the linker.
+    protected final Object mLock = new Object();
 
     // Constants used to control the behaviour of the browser process with
     // regards to the shared RELRO section.
@@ -188,96 +190,24 @@ public class Linker {
     // Indicates if this is a low-memory device or not. The default is to
     // determine this by probing the system at runtime, but this can be forced
     // for testing by calling setMemoryDeviceConfig().
-    private static int sMemoryDeviceConfig = MEMORY_DEVICE_CONFIG_INIT;
-
-    // Becomes true after linker initialization.
-    private static boolean sInitialized = false;
-
-    // Set to true to indicate that the system supports safe sharing of RELRO sections.
-    private static boolean sRelroSharingSupported = false;
-
-    // Set to true if this runs in the browser process. Disabled by initServiceProcess().
-    // TODO(petrcermak): This flag can be incorrectly set to false (even though this might run in
-    // the browser process) on low-memory devices.
-    private static boolean sInBrowserProcess = true;
-
-    // Becomes true to indicate this process needs to wait for a shared RELRO in
-    // finishLibraryLoad().
-    private static boolean sWaitForSharedRelros = false;
-
-    // Becomes true when initialization determines that the browser process can use the
-    // shared RELRO.
-    private static boolean sBrowserUsesSharedRelro = false;
-
-    // The map of all RELRO sections either created or used in this process.
-    private static Bundle sSharedRelros = null;
-
-    // Current common random base load address.
-    private static long sBaseLoadAddress = 0;
-
-    // Current fixed-location load address for the next library called by loadLibrary().
-    private static long sCurrentLoadAddress = 0;
-
-    // Becomes true once prepareLibraryLoad() has been called.
-    private static boolean sPrepareLibraryLoadCalled = false;
-
-    // Used internally to initialize the linker's static data. Assume lock is held.
-    private static void ensureInitializedLocked() {
-        assert Thread.holdsLock(Linker.class);
-
-        if (!sInitialized) {
-            sRelroSharingSupported = false;
-            if (NativeLibraries.sUseLinker) {
-                if (DEBUG) Log.i(TAG, "Loading lib" + TAG + ".so");
-                try {
-                    System.loadLibrary(TAG);
-                } catch (UnsatisfiedLinkError  e) {
-                    // In a component build, the ".cr" suffix is added to each library name.
-                    Log.w(TAG, "Couldn't load lib" + TAG + ".so, trying lib" + TAG + ".cr.so");
-                    System.loadLibrary(TAG + ".cr");
-                }
-                sRelroSharingSupported = nativeCanUseSharedRelro();
-                if (!sRelroSharingSupported) {
-                    Log.w(TAG, "This system cannot safely share RELRO sections");
-                } else {
-                    if (DEBUG) Log.i(TAG, "This system supports safe shared RELRO sections");
-                }
-
-                if (sMemoryDeviceConfig == MEMORY_DEVICE_CONFIG_INIT) {
-                    sMemoryDeviceConfig = SysUtils.isLowEndDevice()
-                            ? MEMORY_DEVICE_CONFIG_LOW : MEMORY_DEVICE_CONFIG_NORMAL;
-                }
-
-                switch (BROWSER_SHARED_RELRO_CONFIG) {
-                    case BROWSER_SHARED_RELRO_CONFIG_NEVER:
-                        sBrowserUsesSharedRelro = false;
-                        break;
-                    case BROWSER_SHARED_RELRO_CONFIG_LOW_RAM_ONLY:
-                        sBrowserUsesSharedRelro =
-                                (sMemoryDeviceConfig == MEMORY_DEVICE_CONFIG_LOW);
-                        if (sBrowserUsesSharedRelro) {
-                            Log.w(TAG, "Low-memory device: shared RELROs used in all processes");
-                        }
-                        break;
-                    case BROWSER_SHARED_RELRO_CONFIG_ALWAYS:
-                        Log.w(TAG, "Beware: shared RELROs used in all processes!");
-                        sBrowserUsesSharedRelro = true;
-                        break;
-                    default:
-                        assert false : "Unreached";
-                        break;
-                }
-            } else {
-                if (DEBUG) Log.i(TAG, "Linker disabled");
+    protected int mMemoryDeviceConfig = MEMORY_DEVICE_CONFIG_INIT;
+
+    // Singleton.
+    private static Linker sSingleton = null;
+    private static Object sSingletonLock = new Object();
+
+    // Protected singleton constructor.
+    protected Linker() {}
+
+    // Get singleton instance.
+    public static final Linker getInstance() {
+        synchronized (sSingletonLock) {
+            if (sSingleton == null) {
+                // TODO(simonb): Extend later to return either a LegacyLinker
+                // or a ModernLinker instance.
+                sSingleton = new LegacyLinker();
             }
-
-            if (!sRelroSharingSupported) {
-                // Sanity.
-                sBrowserUsesSharedRelro = false;
-                sWaitForSharedRelros = false;
-            }
-
-            sInitialized = true;
+            return sSingleton;
         }
     }
 
@@ -297,7 +227,7 @@ public class Linker {
     }
 
     // The name of a class that implements TestRunner.
-    static String sTestRunnerClassName = null;
+    String mTestRunnerClassName = null;
 
     /**
      * Set the TestRunner by its class name. It will be instantiated at
@@ -305,17 +235,18 @@ public class Linker {
      * @param testRunnerClassName null or a String for the class name of the
      * TestRunner to use.
      */
-    public static void setTestRunnerClassName(String testRunnerClassName) {
-        if (DEBUG) Log.i(TAG, "setTestRunnerByClassName(" + testRunnerClassName + ") called");
-
+    public void setTestRunnerClassName(String testRunnerClassName) {
+        if (DEBUG) {
+            Log.i(TAG, "setTestRunnerByClassName(" + testRunnerClassName + ") called");
+        }
         if (!NativeLibraries.sEnableLinkerTests) {
-            // Ignore this in production code to prevent malvolent runtime injection.
+            // Ignore this in production code to prevent malevolent runtime injection.
             return;
         }
 
-        synchronized (Linker.class) {
-            assert sTestRunnerClassName == null;
-            sTestRunnerClassName = testRunnerClassName;
+        synchronized (mLock) {
+            assert mTestRunnerClassName == null;
+            mTestRunnerClassName = testRunnerClassName;
         }
     }
 
@@ -326,9 +257,9 @@ public class Linker {
      * @return null or a String holding the name of the class implementing
      * the TestRunner set by calling setTestRunnerClassName() previously.
      */
-    public static String getTestRunnerClassName() {
-        synchronized (Linker.class) {
-            return sTestRunnerClassName;
+    public String getTestRunnerClassName() {
+        synchronized (mLock) {
+            return mTestRunnerClassName;
         }
     }
 
@@ -337,12 +268,14 @@ public class Linker {
      * memory device configuration. Should only be used for testing.
      * @param memoryDeviceConfig either MEMORY_DEVICE_CONFIG_LOW or MEMORY_DEVICE_CONFIG_NORMAL.
      */
-    public static void setMemoryDeviceConfig(int memoryDeviceConfig) {
-        if (DEBUG) Log.i(TAG, "setMemoryDeviceConfig(" + memoryDeviceConfig + ") called");
+    public void setMemoryDeviceConfig(int memoryDeviceConfig) {
+        if (DEBUG) {
+            Log.i(TAG, "setMemoryDeviceConfig(" + memoryDeviceConfig + ") called");
+        }
         // Sanity check. This method should only be called during tests.
         assert NativeLibraries.sEnableLinkerTests;
-        synchronized (Linker.class) {
-            assert sMemoryDeviceConfig == MEMORY_DEVICE_CONFIG_INIT;
+        synchronized (mLock) {
+            assert mMemoryDeviceConfig == MEMORY_DEVICE_CONFIG_INIT;
             assert memoryDeviceConfig == MEMORY_DEVICE_CONFIG_LOW
                    || memoryDeviceConfig == MEMORY_DEVICE_CONFIG_NORMAL;
             if (DEBUG) {
@@ -352,7 +285,7 @@ public class Linker {
                     Log.i(TAG, "Simulating a regular-memory device");
                 }
             }
-            sMemoryDeviceConfig = memoryDeviceConfig;
+            mMemoryDeviceConfig = memoryDeviceConfig;
         }
     }
 
@@ -361,130 +294,31 @@ public class Linker {
      * use this linker. If not, System.loadLibrary() should be used to load
      * libraries instead.
      */
-    public static boolean isUsed() {
-        // Only GYP targets that are APKs and have the 'use_chromium_linker' variable
-        // defined as 1 will use this linker. For all others (the default), the
-        // auto-generated NativeLibraries.sUseLinker variable will be false.
-        if (!NativeLibraries.sUseLinker) return false;
-
-        synchronized (Linker.class) {
-            ensureInitializedLocked();
-            // At the moment, there is also no point in using this linker if the
-            // system does not support RELRO sharing safely.
-            return sRelroSharingSupported;
-        }
-    }
+    public abstract boolean isUsed();
 
     /**
      * Call this method to determine if the linker will try to use shared RELROs
      * for the browser process.
      */
-    public static boolean isUsingBrowserSharedRelros() {
-        synchronized (Linker.class) {
-            ensureInitializedLocked();
-            return sBrowserUsesSharedRelro;
-        }
-    }
+    public abstract boolean isUsingBrowserSharedRelros();
 
     /**
      * Call this method to determine if the chromium project must load
      * the library directly from the zip file.
      */
-    public static boolean isInZipFile() {
-        return NativeLibraries.sUseLibraryInZipFile;
-    }
+    public abstract boolean isInZipFile();
 
     /**
      * Call this method just before loading any native shared libraries in this process.
      */
-    public static void prepareLibraryLoad() {
-        if (DEBUG) Log.i(TAG, "prepareLibraryLoad() called");
-        synchronized (Linker.class) {
-            sPrepareLibraryLoadCalled = true;
-
-            if (sInBrowserProcess) {
-                // Force generation of random base load address, as well
-                // as creation of shared RELRO sections in this process.
-                setupBaseLoadAddressLocked();
-            }
-        }
-    }
+    public abstract void prepareLibraryLoad();
 
     /**
      * Call this method just after loading all native shared libraries in this process.
      * Note that when in a service process, this will block until the RELRO bundle is
      * received, i.e. when another thread calls useSharedRelros().
      */
-    public static void finishLibraryLoad() {
-        if (DEBUG) Log.i(TAG, "finishLibraryLoad() called");
-        synchronized (Linker.class) {
-            if (DEBUG) Log.i(TAG, String.format(
-                    Locale.US,
-                    "sInBrowserProcess=%s sBrowserUsesSharedRelro=%s sWaitForSharedRelros=%s",
-                    sInBrowserProcess ? "true" : "false",
-                    sBrowserUsesSharedRelro ? "true" : "false",
-                    sWaitForSharedRelros ? "true" : "false"));
-
-            if (sLoadedLibraries == null) {
-                if (DEBUG) Log.i(TAG, "No libraries loaded");
-            } else {
-                if (sInBrowserProcess) {
-                    // Create new Bundle containing RELRO section information
-                    // for all loaded libraries. Make it available to getSharedRelros().
-                    sSharedRelros = createBundleFromLibInfoMap(sLoadedLibraries);
-                    if (DEBUG) {
-                        Log.i(TAG, "Shared RELRO created");
-                        dumpBundle(sSharedRelros);
-                    }
-
-                    if (sBrowserUsesSharedRelro) {
-                        useSharedRelrosLocked(sSharedRelros);
-                    }
-                }
-
-                if (sWaitForSharedRelros) {
-                    assert !sInBrowserProcess;
-
-                    // Wait until the shared relro bundle is received from useSharedRelros().
-                    while (sSharedRelros == null) {
-                        try {
-                            Linker.class.wait();
-                        } catch (InterruptedException ie) {
-                            // no-op
-                        }
-                    }
-                    useSharedRelrosLocked(sSharedRelros);
-                    // Clear the Bundle to ensure its file descriptor references can't be reused.
-                    sSharedRelros.clear();
-                    sSharedRelros = null;
-                }
-            }
-
-            if (NativeLibraries.sEnableLinkerTests && sTestRunnerClassName != null) {
-                // The TestRunner implementation must be instantiated _after_
-                // all libraries are loaded to ensure that its native methods
-                // are properly registered.
-                if (DEBUG) Log.i(TAG, "Instantiating " + sTestRunnerClassName);
-                TestRunner testRunner = null;
-                try {
-                    testRunner = (TestRunner)
-                            Class.forName(sTestRunnerClassName).newInstance();
-                } catch (Exception e) {
-                    Log.e(TAG, "Could not extract test runner class name", e);
-                    testRunner = null;
-                }
-                if (testRunner != null) {
-                    if (!testRunner.runChecks(sMemoryDeviceConfig, sInBrowserProcess)) {
-                        Log.wtf(TAG, "Linker runtime tests failed in this process!!");
-                        assert false;
-                    } else {
-                        Log.i(TAG, "All linker tests passed!");
-                    }
-                }
-            }
-        }
-        if (DEBUG) Log.i(TAG, "finishLibraryLoad() exiting");
-    }
+    public abstract void finishLibraryLoad();
 
     /**
      * Call this to send a Bundle containing the shared RELRO sections to be
@@ -494,32 +328,7 @@ public class Linker {
      * @param bundle The Bundle instance containing a map of shared RELRO sections
      * to use in this process.
      */
-    public static void useSharedRelros(Bundle bundle) {
-        // Ensure the bundle uses the application's class loader, not the framework
-        // one which doesn't know anything about LibInfo.
-        // Also, hold a fresh copy of it so the caller can't recycle it.
-        Bundle clonedBundle = null;
-        if (bundle != null) {
-            bundle.setClassLoader(LibInfo.class.getClassLoader());
-            clonedBundle = new Bundle(LibInfo.class.getClassLoader());
-            Parcel parcel = Parcel.obtain();
-            bundle.writeToParcel(parcel, 0);
-            parcel.setDataPosition(0);
-            clonedBundle.readFromParcel(parcel);
-            parcel.recycle();
-        }
-        if (DEBUG) {
-            Log.i(TAG, "useSharedRelros() called with " + bundle
-                    + ", cloned " + clonedBundle);
-        }
-        synchronized (Linker.class) {
-            // Note that in certain cases, this can be called before
-            // initServiceProcess() in service processes.
-            sSharedRelros = clonedBundle;
-            // Tell any listener blocked in finishLibraryLoad() about it.
-            Linker.class.notifyAll();
-        }
-    }
+    public abstract void useSharedRelros(Bundle bundle);
 
     /**
      * Call this to retrieve the shared RELRO sections created in this process,
@@ -527,33 +336,13 @@ public class Linker {
      * @return a new Bundle instance, or null if RELRO sharing is disabled on
      * this system, or if initServiceProcess() was called previously.
      */
-    public static Bundle getSharedRelros() {
-        if (DEBUG) Log.i(TAG, "getSharedRelros() called");
-        synchronized (Linker.class) {
-            if (!sInBrowserProcess) {
-                if (DEBUG) Log.i(TAG, "... returning null Bundle");
-                return null;
-            }
-
-            // Return the Bundle created in finishLibraryLoad().
-            if (DEBUG) Log.i(TAG, "... returning " + sSharedRelros);
-            return sSharedRelros;
-        }
-    }
-
+    public abstract Bundle getSharedRelros();
 
     /**
      * Call this method before loading any libraries to indicate that this
      * process shall neither create or reuse shared RELRO sections.
      */
-    public static void disableSharedRelros() {
-        if (DEBUG) Log.i(TAG, "disableSharedRelros() called");
-        synchronized (Linker.class) {
-            sInBrowserProcess = false;
-            sWaitForSharedRelros = false;
-            sBrowserUsesSharedRelro = false;
-        }
-    }
+    public abstract void disableSharedRelros();
 
     /**
      * Call this method before loading any libraries to indicate that this
@@ -561,22 +350,7 @@ public class Linker {
      * Typically used when starting service processes.
      * @param baseLoadAddress the base library load address to use.
      */
-    public static void initServiceProcess(long baseLoadAddress) {
-        if (DEBUG) {
-            Log.i(TAG, String.format(
-                    Locale.US, "initServiceProcess(0x%x) called", baseLoadAddress));
-        }
-        synchronized (Linker.class) {
-            ensureInitializedLocked();
-            sInBrowserProcess = false;
-            sBrowserUsesSharedRelro = false;
-            if (sRelroSharingSupported) {
-                sWaitForSharedRelros = true;
-                sBaseLoadAddress = baseLoadAddress;
-                sCurrentLoadAddress = baseLoadAddress;
-            }
-        }
-    }
+    public abstract void initServiceProcess(long baseLoadAddress);
 
     /**
      * Retrieve the base load address of all shared RELRO sections.
@@ -585,119 +359,7 @@ public class Linker {
      * @return a common, random base load address, or 0 if RELRO sharing is
      * disabled.
      */
-    public static long getBaseLoadAddress() {
-        synchronized (Linker.class) {
-            ensureInitializedLocked();
-            if (!sInBrowserProcess) {
-                Log.w(TAG, "Shared RELRO sections are disabled in this process!");
-                return 0;
-            }
-
-            setupBaseLoadAddressLocked();
-            if (DEBUG) Log.i(TAG, String.format(Locale.US, "getBaseLoadAddress() returns 0x%x",
-                                                sBaseLoadAddress));
-            return sBaseLoadAddress;
-        }
-    }
-
-    // Used internally to lazily setup the common random base load address.
-    private static void setupBaseLoadAddressLocked() {
-        assert Thread.holdsLock(Linker.class);
-        if (sBaseLoadAddress == 0) {
-            long address = computeRandomBaseLoadAddress();
-            sBaseLoadAddress = address;
-            sCurrentLoadAddress = address;
-            if (address == 0) {
-                // If the computed address is 0, there are issues with finding enough
-                // free address space, so disable RELRO shared / fixed load addresses.
-                Log.w(TAG, "Disabling shared RELROs due address space pressure");
-                sBrowserUsesSharedRelro = false;
-                sWaitForSharedRelros = false;
-            }
-        }
-    }
-
-
-    /**
-     * Compute a random base load address at which to place loaded libraries.
-     * @return new base load address, or 0 if the system does not support
-     * RELRO sharing.
-     */
-    private static long computeRandomBaseLoadAddress() {
-        // nativeGetRandomBaseLoadAddress() returns an address at which it has previously
-        // successfully mapped an area of the given size, on the basis that we will be
-        // able, with high probability, to map our library into it.
-        //
-        // One issue with this is that we do not yet know the size of the library that
-        // we will load is. So here we pass a value that we expect will always be larger
-        // than that needed. If it is smaller the library mapping may still succeed. The
-        // other issue is that although highly unlikely, there is no guarantee that
-        // something else does not map into the area we are going to use between here and
-        // when we try to map into it.
-        //
-        // The above notes mean that all of this is probablistic. It is however okay to do
-        // because if, worst case and unlikely, we get unlucky in our choice of address,
-        // the back-out and retry without the shared RELRO in the ChildProcessService will
-        // keep things running.
-        final long maxExpectedBytes = 192 * 1024 * 1024;
-        final long address = nativeGetRandomBaseLoadAddress(maxExpectedBytes);
-        if (DEBUG) {
-            Log.i(TAG, String.format(Locale.US, "Random native base load address: 0x%x", address));
-        }
-        return address;
-    }
-
-    // Used for debugging only.
-    private static void dumpBundle(Bundle bundle) {
-        if (DEBUG) Log.i(TAG, "Bundle has " + bundle.size() + " items: " + bundle);
-    }
-
-    /**
-     * Use the shared RELRO section from a Bundle received form another process.
-     * Call this after calling setBaseLoadAddress() then loading all libraries
-     * with loadLibrary().
-     * @param bundle Bundle instance generated with createSharedRelroBundle() in
-     * another process.
-     */
-    private static void useSharedRelrosLocked(Bundle bundle) {
-        assert Thread.holdsLock(Linker.class);
-
-        if (DEBUG) Log.i(TAG, "Linker.useSharedRelrosLocked() called");
-
-        if (bundle == null) {
-            if (DEBUG) Log.i(TAG, "null bundle!");
-            return;
-        }
-
-        if (!sRelroSharingSupported) {
-            if (DEBUG) Log.i(TAG, "System does not support RELRO sharing");
-            return;
-        }
-
-        if (sLoadedLibraries == null) {
-            if (DEBUG) Log.i(TAG, "No libraries loaded!");
-            return;
-        }
-
-        if (DEBUG) dumpBundle(bundle);
-        HashMap<String, LibInfo> relroMap = createLibInfoMapFromBundle(bundle);
-
-        // Apply the RELRO section to all libraries that were already loaded.
-        for (Map.Entry<String, LibInfo> entry : relroMap.entrySet()) {
-            String libName = entry.getKey();
-            LibInfo libInfo = entry.getValue();
-            if (!nativeUseSharedRelro(libName, libInfo)) {
-                Log.w(TAG, "Could not use shared RELRO section for " + libName);
-            } else {
-                if (DEBUG) Log.i(TAG, "Using shared RELRO section for " + libName);
-            }
-        }
-
-        // In service processes, close all file descriptors from the map now.
-        if (!sInBrowserProcess) closeLibInfoMap(relroMap);
-
-        if (DEBUG) Log.i(TAG, "Linker.useSharedRelrosLocked() exiting");
-    }
+    public abstract long getBaseLoadAddress();
 
     /**
      * Load a native shared library with the Chromium linker. If the zip file
@@ -709,254 +371,13 @@ public class Linker {
      * @param zipFilePath The path of the zip file containing the library (or null).
      * @param libFilePath The path of the library (possibly in the zip file).
      */
-    public static void loadLibrary(@Nullable String zipFilePath, String libFilePath) {
-        if (DEBUG) Log.i(TAG, "loadLibrary: " + zipFilePath + ", " + libFilePath);
-
-        synchronized (Linker.class) {
-            ensureInitializedLocked();
-
-            // Security: Ensure prepareLibraryLoad() was called before.
-            // In theory, this can be done lazily here, but it's more consistent
-            // to use a pair of functions (i.e. prepareLibraryLoad() + finishLibraryLoad())
-            // that wrap all calls to loadLibrary() in the library loader.
-            assert sPrepareLibraryLoadCalled;
-
-            if (sLoadedLibraries == null) sLoadedLibraries = new HashMap<String, LibInfo>();
-
-            if (sLoadedLibraries.containsKey(libFilePath)) {
-                if (DEBUG) Log.i(TAG, "Not loading " + libFilePath + " twice");
-                return;
-            }
-
-            LibInfo libInfo = new LibInfo();
-            long loadAddress = 0;
-            if ((sInBrowserProcess && sBrowserUsesSharedRelro) || sWaitForSharedRelros) {
-                // Load the library at a fixed address.
-                loadAddress = sCurrentLoadAddress;
-            }
-
-            String sharedRelRoName = libFilePath;
-            if (zipFilePath != null) {
-                if (!nativeLoadLibraryInZipFile(zipFilePath, libFilePath, loadAddress, libInfo)) {
-                    String errorMessage = "Unable to load library: " + libFilePath
-                                          + ", in: " + zipFilePath;
-                    Log.e(TAG, errorMessage);
-                    throw new UnsatisfiedLinkError(errorMessage);
-                }
-                sharedRelRoName = zipFilePath;
-            } else {
-                if (!nativeLoadLibrary(libFilePath, loadAddress, libInfo)) {
-                    String errorMessage = "Unable to load library: " + libFilePath;
-                    Log.e(TAG, errorMessage);
-                    throw new UnsatisfiedLinkError(errorMessage);
-                }
-            }
-
-            // Print the load address to the logcat when testing the linker. The format
-            // of the string is expected by the Python test_runner script as one of:
-            //    BROWSER_LIBRARY_ADDRESS: <library-name> <address>
-            //    RENDERER_LIBRARY_ADDRESS: <library-name> <address>
-            // Where <library-name> is the library name, and <address> is the hexadecimal load
-            // address.
-            if (NativeLibraries.sEnableLinkerTests) {
-                Log.i(TAG, String.format(
-                        Locale.US,
-                        "%s_LIBRARY_ADDRESS: %s %x",
-                        sInBrowserProcess ? "BROWSER" : "RENDERER",
-                        libFilePath,
-                        libInfo.mLoadAddress));
-            }
-
-            if (sInBrowserProcess) {
-                // Create a new shared RELRO section at the 'current' fixed load address.
-                if (!nativeCreateSharedRelro(sharedRelRoName, sCurrentLoadAddress, libInfo)) {
-                    Log.w(TAG, String.format(Locale.US,
-                            "Could not create shared RELRO for %s at %x", libFilePath,
-                            sCurrentLoadAddress));
-                } else {
-                    if (DEBUG) Log.i(TAG,
-                        String.format(
-                            Locale.US,
-                            "Created shared RELRO for %s at %x: %s",
-                            sharedRelRoName,
-                            sCurrentLoadAddress,
-                            libInfo.toString()));
-                }
-            }
-
-            if (sCurrentLoadAddress != 0) {
-                // Compute the next current load address. If sBaseLoadAddress
-                // is not 0, this is an explicit library load address. Otherwise,
-                // this is an explicit load address for relocated RELRO sections
-                // only.
-                sCurrentLoadAddress = libInfo.mLoadAddress + libInfo.mLoadSize;
-            }
-
-            sLoadedLibraries.put(sharedRelRoName, libInfo);
-            if (DEBUG) Log.i(TAG, "Library details " + libInfo.toString());
-        }
-    }
+    public abstract void loadLibrary(@Nullable String zipFilePath, String libFilePath);
 
     /**
      * Determine whether a library is the linker library. Also deal with the
      * component build that adds a .cr suffix to the name.
      */
-    public static boolean isChromiumLinkerLibrary(String library) {
-        return library.equals(TAG) || library.equals(TAG + ".cr");
-    }
-
-    /**
-     * Get the full library path in zip file (lib/<abi>/crazy.<lib_name>).
-     *
-     * @param library The library's base name.
-     * @return the library path.
-     */
-    public static String getLibraryFilePathInZipFile(String library) throws FileNotFoundException {
-        synchronized (Linker.class) {
-            ensureInitializedLocked();
-
-            String path = nativeGetLibraryFilePathInZipFile(library);
-            if (path.equals("")) {
-                throw new FileNotFoundException(
-                        "Failed to retrieve path in zip file for library " + library);
-            }
-            return path;
-        }
-    }
-
-    /**
-     * Check whether a library is page aligned and uncompressed in the APK file.
-     *
-     * @param apkFile Filename of the APK.
-     * @param library The library's base name.
-     * @return true if page aligned and uncompressed.
-     */
-    public static boolean checkLibraryIsMappableInApk(String apkFile, String library) {
-        synchronized (Linker.class) {
-            ensureInitializedLocked();
-
-            if (DEBUG) Log.i(TAG, "checkLibraryIsMappableInApk: " + apkFile + ", " + library);
-            boolean aligned = nativeCheckLibraryIsMappableInApk(apkFile, library);
-            if (DEBUG) Log.i(TAG, library + " is " + (aligned ? "" : "NOT ")
-                    + "page aligned in " + apkFile);
-            return aligned;
-        }
-    }
-
-    /**
-     * Move activity from the native thread to the main UI thread.
-     * Called from native code on its own thread.  Posts a callback from
-     * the UI thread back to native code.
-     *
-     * @param opaque Opaque argument.
-     */
-    @CalledByNative
-    public static void postCallbackOnMainThread(final long opaque) {
-        ThreadUtils.postOnUiThread(new Runnable() {
-            @Override
-            public void run() {
-                nativeRunCallbackOnUiThread(opaque);
-            }
-        });
-    }
-
-    /**
-     * Native method to run callbacks on the main UI thread.
-     * Supplied by the crazy linker and called by postCallbackOnMainThread.
-     * @param opaque Opaque crazy linker arguments.
-     */
-    private static native void nativeRunCallbackOnUiThread(long opaque);
-
-    /**
-     * Native method used to load a library.
-     * @param library Platform specific library name (e.g. libfoo.so)
-     * @param loadAddress Explicit load address, or 0 for randomized one.
-     * @param libInfo If not null, the mLoadAddress and mLoadSize fields
-     * of this LibInfo instance will set on success.
-     * @return true for success, false otherwise.
-     */
-    private static native boolean nativeLoadLibrary(String library,
-                                                    long loadAddress,
-                                                    LibInfo libInfo);
-
-    /**
-     * Native method used to load a library which is inside a zipfile.
-     * @param zipfileName Filename of the zip file containing the library.
-     * @param library Platform specific library name (e.g. libfoo.so)
-     * @param loadAddress Explicit load address, or 0 for randomized one.
-     * @param libInfo If not null, the mLoadAddress and mLoadSize fields
-     * of this LibInfo instance will set on success.
-     * @return true for success, false otherwise.
-     */
-    private static native boolean nativeLoadLibraryInZipFile(String zipfileName,
-                                                             String libraryName,
-                                                             long loadAddress,
-                                                             LibInfo libInfo);
-
-    /**
-     * Native method used to create a shared RELRO section.
-     * If the library was already loaded at the same address using
-     * nativeLoadLibrary(), this creates the RELRO for it. Otherwise,
-     * this loads a new temporary library at the specified address,
-     * creates and extracts the RELRO section from it, then unloads it.
-     * @param library Library name.
-     * @param loadAddress load address, which can be different from the one
-     * used to load the library in the current process!
-     * @param libInfo libInfo instance. On success, the mRelroStart, mRelroSize
-     * and mRelroFd will be set.
-     * @return true on success, false otherwise.
-     */
-    private static native boolean nativeCreateSharedRelro(String library,
-                                                          long loadAddress,
-                                                          LibInfo libInfo);
-
-    /**
-     * Native method used to use a shared RELRO section.
-     * @param library Library name.
-     * @param libInfo A LibInfo instance containing valid RELRO information
-     * @return true on success.
-     */
-    private static native boolean nativeUseSharedRelro(String library,
-                                                       LibInfo libInfo);
-
-    /**
-     * Checks that the system supports shared RELROs. Old Android kernels
-     * have a bug in the way they check Ashmem region protection flags, which
-     * makes using shared RELROs unsafe. This method performs a simple runtime
-     * check for this misfeature, even though nativeEnableSharedRelro() will
-     * always fail if this returns false.
-     */
-    private static native boolean nativeCanUseSharedRelro();
-
-    /**
-     * Return a random address that should be free to be mapped with the given size.
-     * Maps an area of size bytes, and if successful then unmaps it and returns
-     * the address of the area allocated by the system (with ASLR). The idea is
-     * that this area should remain free of other mappings until we map our library
-     * into it.
-     * @param sizeBytes Size of area in bytes to search for.
-     * @return address to pass to future mmap, or 0 on error.
-     */
-    private static native long nativeGetRandomBaseLoadAddress(long sizeBytes);
-
-    /**
-      * Native method used to get the full library path in zip file
-      * (lib/<abi>/crazy.<lib_name>).
-      *
-      * @param library The library's base name.
-      * @return the library path (or empty string on failure).
-      */
-    private static native String nativeGetLibraryFilePathInZipFile(String library);
-
-    /**
-     * Native method which checks whether a library is page aligned and
-     * uncompressed in the APK file.
-     *
-     * @param apkFile Filename of the APK.
-     * @param library The library's base name.
-     * @return true if page aligned and uncompressed.
-     */
-    private static native boolean nativeCheckLibraryIsMappableInApk(String apkFile, String library);
+    public abstract boolean isChromiumLinkerLibrary(String library);
 
     /**
      * Record information for a given library.
@@ -979,7 +400,9 @@ public class Linker {
                 try {
                     ParcelFileDescriptor.adoptFd(mRelroFd).close();
                 } catch (java.io.IOException e) {
-                    if (DEBUG) Log.e(TAG, "Failed to close fd: " + mRelroFd);
+                    if (DEBUG) {
+                        Log.e(TAG, "Failed to close fd: " + mRelroFd);
+                    }
                 }
                 mRelroFd = -1;
             }
@@ -1060,7 +483,7 @@ public class Linker {
     }
 
     // Create a Bundle from a map of LibInfo objects.
-    private static Bundle createBundleFromLibInfoMap(HashMap<String, LibInfo> map) {
+    protected Bundle createBundleFromLibInfoMap(HashMap<String, LibInfo> map) {
         Bundle bundle = new Bundle(map.size());
         for (Map.Entry<String, LibInfo> entry : map.entrySet()) {
             bundle.putParcelable(entry.getKey(), entry.getValue());
@@ -1070,7 +493,7 @@ public class Linker {
     }
 
     // Create a new LibInfo map from a Bundle.
-    private static HashMap<String, LibInfo> createLibInfoMapFromBundle(Bundle bundle) {
+    protected HashMap<String, LibInfo> createLibInfoMapFromBundle(Bundle bundle) {
         HashMap<String, LibInfo> map = new HashMap<String, LibInfo>();
         for (String library : bundle.keySet()) {
             LibInfo libInfo = bundle.getParcelable(library);
@@ -1080,16 +503,9 @@ public class Linker {
     }
 
     // Call the close() method on all values of a LibInfo map.
-    private static void closeLibInfoMap(HashMap<String, LibInfo> map) {
+    protected void closeLibInfoMap(HashMap<String, LibInfo> map) {
         for (Map.Entry<String, LibInfo> entry : map.entrySet()) {
             entry.getValue().close();
         }
     }
-
-    // The map of libraries that are currently loaded in this process.
-    private static HashMap<String, LibInfo> sLoadedLibraries = null;
-
-    // Used to pass the shared RELRO Bundle through Binder.
-    public static final String EXTRA_LINKER_SHARED_RELROS =
-            "org.chromium.base.android.linker.shared_relros";
 }