[Android] Add gyp support for multidex.

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index b6fb63eda7224a74168ba28a113d25ded6daeb26..a4e5a5c028da25da06f1b5202a6cd67456d6a6f6 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -1591,6 +1591,7 @@ if (is_android) {
     ]
 
     deps = [
+      "//third_party/android_tools:android_support_multidex_java",
       "//third_party/jsr-305:jsr_305_javalib",
     ]
 
@@ -1622,12 +1623,29 @@ if (is_android) {
     DEPRECATED_java_in_dir = "test/android/javatests/src"
   }
 
+  # TODO(jbudorick): Remove this once we roll to robolectric 3.0 and pull
+  # in the multidex shadow library. crbug.com/522043
+  # GYP: //base.gyp:base_junit_test_support
+  java_library("base_junit_test_support") {
+    testonly = true
+    java_files = [ "test/android/junit/src/org/chromium/base/test/shadows/ShadowMultiDex.java" ]
+    deps = [
+      "//third_party/android_tools:android_support_multidex_java",
+      "//third_party/robolectric:android-all-4.3_r2-robolectric-0",
+      "//third_party/robolectric:robolectric_java",
+    ]
+  }
+
   # GYP: //base.gyp:base_junit_tests
   junit_binary("base_junit_tests") {
-    java_files = [ "android/junit/src/org/chromium/base/LogTest.java" ]
+    java_files = [
+      "android/junit/src/org/chromium/base/BaseChromiumApplicationTest.java",
+      "android/junit/src/org/chromium/base/LogTest.java",
+    ]
     deps = [
       ":base_java",
       ":base_java_test_support",
+      ":base_junit_test_support",
     ]
   }