Revert of 🍈 Unify application context usage.

base/android/java/src/org/chromium/base/ContextUtils.java

Index: base/android/java/src/org/chromium/base/ContextUtils.java
diff --git a/base/android/java/src/org/chromium/base/ContextUtils.java b/base/android/java/src/org/chromium/base/ContextUtils.java
index 95cdc4015348dd0af75da09e14d0955f82f22edb..51adcff8f67375a4bf0507fedfeecf72daa07396 100644
--- a/base/android/java/src/org/chromium/base/ContextUtils.java
+++ b/base/android/java/src/org/chromium/base/ContextUtils.java
@@ -6,6 +6,7 @@
 
 import android.content.Context;
 
+import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
 
 /**
@@ -13,7 +14,6 @@
  */
 @JNINamespace("base::android")
 public class ContextUtils {
-    private static final String TAG = "ContextUtils";
     private static Context sApplicationContext;
 
     /**
@@ -29,52 +29,34 @@
      * may make is that it is a Context whose lifetime is the same as the lifetime of the process.
      */
     public static Context getApplicationContext() {
+        assert sApplicationContext != null;
         return sApplicationContext;
     }
 
     /**
-     * Initializes the java application context.
+     * Initialize the Android application context.
      *
-     * This should be called exactly once early on during startup, before native is loaded and
-     * before any other clients make use of the application context through this class.
-     *
-     * @param appContext The application context.
+     * Either this or the native equivalent base::android::InitApplicationContext must be called
+     * once during startup. JNI bindings must have been initialized, as the context is stored on
+     * both sides.
      */
     public static void initApplicationContext(Context appContext) {
-        // Conceding that occasionally in tests, native is loaded before the browser process is
-        // started, in which case the browser process re-sets the application context.
-        if (sApplicationContext != null && sApplicationContext != appContext) {
-            throw new RuntimeException("Attempting to set multiple global application contexts.");
-        }
+        assert appContext != null;
+        assert sApplicationContext == null || sApplicationContext == appContext;
+        initJavaSideApplicationContext(appContext);
+        nativeInitNativeSideApplicationContext(appContext);
+    }
+
+    /**
+     * JUnit Robolectric tests run without native code; allow them to set just the Java-side
+     * context. Do not use in configurations that actually run on Android!
+     */
+    public static void initApplicationContextForJUnitTests(Context appContext) {
         initJavaSideApplicationContext(appContext);
     }
 
-    /**
-     * Initialize the native Android application context to be the same as the java counter-part.
-     */
-    public static void initApplicationContextForNative() {
-        if (sApplicationContext == null) {
-            throw new RuntimeException("Cannot have native global application context be null.");
-        }
-        nativeInitNativeSideApplicationContext(sApplicationContext);
-    }
-
-    /**
-     * Occasionally tests cannot ensure the application context doesn't change between tests (junit)
-     * and sometimes specific tests has its own special needs, initApplicationContext should be used
-     * as much as possible, but this method can be used to override it.
-     *
-     * @param appContext The new application context.
-     */
-    @VisibleForTesting
-    public static void initApplicationContextForTests(Context appContext) {
-        initJavaSideApplicationContext(appContext);
-    }
-
+    @CalledByNative
     private static void initJavaSideApplicationContext(Context appContext) {
-        if (appContext == null) {
-            throw new RuntimeException("Global application context cannot be set to null.");
-        }
         sApplicationContext = appContext;
     }