[Android] Rework multidex and enable multidex for unit_tests_apk. (RELAND 2)

this is a reland of https://codereview.chromium.org/1590243003/

BUG=272790
TBR=thakis@chromium.org,yfriedman@chromium.org,phajdan.jr@chromium.org

Review URL: https://codereview.chromium.org/1594653002

Cr-Commit-Position: refs/heads/master@{#369906}

3 files changed, 126 insertions, 105 deletions

diff --git a/base/android/java/src/org/chromium/base/BaseChromiumApplication.java b/base/android/java/src/org/chromium/base/BaseChromiumApplication.java
index e4e6e20..f842a18 100644
--- a/base/android/java/src/org/chromium/base/BaseChromiumApplication.java
+++ b/base/android/java/src/org/chromium/base/BaseChromiumApplication.java
@@ -10,7 +10,7 @@ import android.content.Context;
 import android.os.Bundle;
 import android.view.Window;
 
-import org.chromium.base.multidex.ChromiumMultiDex;
+import org.chromium.base.multidex.ChromiumMultiDexInstaller;
 
 /**
  * Basic application functionality that should be shared among all browser applications.
@@ -31,7 +31,7 @@ public class BaseChromiumApplication extends Application {
     @Override
     protected void attachBaseContext(Context base) {
         super.attachBaseContext(base);
-        ChromiumMultiDex.install(this);
+        ChromiumMultiDexInstaller.install(this);
     }
 
     /**
diff --git a/base/android/java/src/org/chromium/base/multidex/ChromiumMultiDexInstaller.java b/base/android/java/src/org/chromium/base/multidex/ChromiumMultiDexInstaller.java
new file mode 100644
index 0000000..e4b30b9
--- /dev/null
+++ b/base/android/java/src/org/chromium/base/multidex/ChromiumMultiDexInstaller.java
@@ -0,0 +1,114 @@
+// 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.
+
+package org.chromium.base.multidex;
+
+import android.app.ActivityManager;
+import android.app.ActivityManager.RunningAppProcessInfo;
+import android.content.Context;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.os.Build;
+import android.support.multidex.MultiDex;
+
+import org.chromium.base.Log;
+import org.chromium.base.VisibleForTesting;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+/**
+ *  Performs multidex installation for non-isolated processes.
+ */
+public class ChromiumMultiDexInstaller {
+
+    private static final String TAG = "base_multidex";
+
+    /**
+     * Suffix for the meta-data tag in the AndroidManifext.xml that determines whether loading
+     * secondary dexes should be skipped for a given process name.
+     */
+    private static final String IGNORE_MULTIDEX_KEY = ".ignore_multidex";
+
+    /**
+     *  Installs secondary dexes if possible/necessary.
+     *
+     *  Isolated processes (e.g. renderer processes) can't load secondary dex files on
+     *  K and below, so we don't even try in that case.
+     *
+     *  In release builds of app apks (as opposed to test apks), this is a no-op because:
+     *    - multidex isn't necessary in release builds because we run proguard there and
+     *      thus aren't threatening to hit the dex limit; and
+     *    - calling MultiDex.install, even in the absence of secondary dexes, causes a
+     *      significant regression in start-up time (crbug.com/525695).
+     *
+     *  @param context The application context.
+     */
+    @VisibleForTesting
+    public static void install(Context context) {
+        if (!ChromiumMultiDex.isMultidexEnabled()) return;
+
+        // TODO(jbudorick): Back out this version check once support for K & below works.
+        // http://crbug.com/512357
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP
+                && !shouldInstallMultiDex(context)) {
+            Log.i(TAG, "Skipping multidex installation: not needed for process.");
+        } else {
+            MultiDex.install(context);
+            Log.i(TAG, "Completed multidex installation.");
+        }
+    }
+
+    private static String getProcessName(Context context) {
+        try {
+            String currentProcessName = null;
+            int pid = android.os.Process.myPid();
+
+            ActivityManager manager =
+                    (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
+            for (RunningAppProcessInfo processInfo : manager.getRunningAppProcesses()) {
+                if (processInfo.pid == pid) {
+                    currentProcessName = processInfo.processName;
+                    break;
+                }
+            }
+
+            return currentProcessName;
+        } catch (SecurityException ex) {
+            return null;
+        }
+    }
+
+    // Determines whether MultiDex should be installed for the current process.  Isolated
+    // Processes should skip MultiDex as they can not actually access the files on disk.
+    // Privileged processes need ot have all of their dependencies in the MainDex for
+    // performance reasons.
+    private static boolean shouldInstallMultiDex(Context context) {
+        try {
+            Method isIsolatedMethod =
+                    android.os.Process.class.getMethod("isIsolated");
+            Object retVal = isIsolatedMethod.invoke(null);
+            if (retVal != null && retVal instanceof Boolean && ((Boolean) retVal)) {
+                return false;
+            }
+        } catch (IllegalAccessException | IllegalArgumentException
+                | InvocationTargetException | NoSuchMethodException e) {
+            // Ignore and fall back to checking the app processes.
+        }
+
+        String currentProcessName = getProcessName(context);
+        if (currentProcessName == null) return true;
+
+        PackageManager packageManager = context.getPackageManager();
+        try {
+            ApplicationInfo appInfo = packageManager.getApplicationInfo(context.getPackageName(),
+                    PackageManager.GET_META_DATA);
+            if (appInfo == null || appInfo.metaData == null) return true;
+            return !appInfo.metaData.getBoolean(currentProcessName + IGNORE_MULTIDEX_KEY, false);
+        } catch (PackageManager.NameNotFoundException e) {
+            return true;
+        }
+    }
+
+}
diff --git a/base/android/java/templates/ChromiumMultiDex.template b/base/android/java/templates/ChromiumMultiDex.template
index 5580489..7e70701 100644
--- a/base/android/java/templates/ChromiumMultiDex.template
+++ b/base/android/java/templates/ChromiumMultiDex.template
@@ -4,115 +4,22 @@
 
 package org.chromium.base.multidex;
 
-import android.app.ActivityManager;
-import android.app.ActivityManager.RunningAppProcessInfo;
-import android.content.Context;
-import android.content.pm.ApplicationInfo;
-import android.content.pm.PackageManager;
-import android.os.Build;
-import android.os.Process;
-import android.support.multidex.MultiDex;
-
-import org.chromium.base.Log;
-import org.chromium.base.VisibleForTesting;
-
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-
 /**
- *  Performs multidex installation for non-isolated processes.
+ *  Multidex configuration. Generated on a per-target basis.
  */
-public class ChromiumMultiDex {
+class ChromiumMultiDex {
 
-    private static final String TAG = "base_multidex";
-
-    /**
-     * Suffix for the meta-data tag in the AndroidManifext.xml that determines whether loading
-     * secondary dexes should be skipped for a given process name.
-     */
-    private static final String IGNORE_MULTIDEX_KEY = ".ignore_multidex";
-
-    /**
-     *  Installs secondary dexes if possible/necessary.
-     *
-     *  Isolated processes (e.g. renderer processes) can't load secondary dex files on
-     *  K and below, so we don't even try in that case.
+    /** Whether multidex is enabled for this target.
      *
-     *  In release builds, this is a no-op because:
-     *    - multidex isn't necessary in release builds because we run proguard there and
-     *      thus aren't threatening to hit the dex limit; and
-     *    - calling MultiDex.install, even in the absence of secondary dexes, causes a
-     *      significant regression in start-up time (crbug.com/525695).
-     *
-     *  @param context The application context.
+     *  This has to be a function instead of a static final boolean s.t. the initial false value
+     *  doesn't get optimized into {@link ChromiumMultiDexInstaller} at base_java compile time.
      */
-    @VisibleForTesting
-#if defined(MULTIDEX_CONFIGURATION_Debug)
-    public static void install(Context context) {
-        // TODO(jbudorick): Back out this version check once support for K & below works.
-        // http://crbug.com/512357
-        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP
-                && !shouldInstallMultiDex(context)) {
-            Log.i(TAG, "Skipping multidex installation: not needed for process.");
-        } else {
-            MultiDex.install(context);
-            Log.i(TAG, "Completed multidex installation.");
-        }
-    }
-
-    private static String getProcessName(Context context) {
-        try {
-            String currentProcessName = null;
-            int pid = android.os.Process.myPid();
-
-            ActivityManager manager =
-                    (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
-            for (RunningAppProcessInfo processInfo : manager.getRunningAppProcesses()) {
-                if (processInfo.pid == pid) {
-                    currentProcessName = processInfo.processName;
-                    break;
-                }
-            }
-
-            return currentProcessName;
-        } catch (SecurityException ex) {
-            return null;
-        }
-    }
-
-    // Determines whether MultiDex should be installed for the current process.  Isolated
-    // Processes should skip MultiDex as they can not actually access the files on disk.
-    // Privileged processes need ot have all of their dependencies in the MainDex for
-    // performance reasons. 
-    private static boolean shouldInstallMultiDex(Context context) {
-        try {
-            Method isIsolatedMethod =
-                    android.os.Process.class.getMethod("isIsolated");
-            Object retVal = isIsolatedMethod.invoke(null);
-            if (retVal != null && retVal instanceof Boolean && ((Boolean) retVal)) {
-                return false;
-            }
-        } catch (IllegalAccessException | IllegalArgumentException
-                | InvocationTargetException | NoSuchMethodException e) {
-            // Ignore and fall back to checking the app processes.
-        }
-
-        String currentProcessName = getProcessName(context);
-        if (currentProcessName == null) return true;
-        
-        PackageManager packageManager = context.getPackageManager();
-        try {
-            ApplicationInfo appInfo = packageManager.getApplicationInfo(context.getPackageName(),
-                    PackageManager.GET_META_DATA);
-            if (appInfo == null || appInfo.metaData == null) return true;
-            return !appInfo.metaData.getBoolean(currentProcessName + IGNORE_MULTIDEX_KEY, false);
-        } catch (PackageManager.NameNotFoundException e) {
-            return true;
-        }
-    }
+    static boolean isMultidexEnabled() {
+#if defined(ENABLE_MULTIDEX)
+        return true;
 #else
-    public static void install(Context context) {
-    }
+        return false;
 #endif
+    }
 
 }