Fixing tests dependencies.

For some reason these problems are found only when doing
'gn gen --check' (which is what builtbot does).

BUG=
TBR=krasin@chromium.org

Review URL: https://codereview.chromium.org/1411413007

Cr-Commit-Position: refs/heads/master@{#356594}

testing/libfuzzer/BUILD.gn

@@ -68,6 +68,7 @@ test("es_parser_adts_fuzzer") {
   ]
   deps = [
     ":libfuzzer_main",
+    "//base",
     "//media",
   ]
 }
@@ -78,6 +79,7 @@ test("es_parser_h264_fuzzer") {
   ]
   deps = [
     ":libfuzzer_main",
+    "//base",
     "//media",
   ]
 }
@@ -88,6 +90,7 @@ test("es_parser_mpeg1audio_fuzzer") {
   ]
   deps = [
     ":libfuzzer_main",
+    "//base",
     "//media",
   ]
 }
@@ -120,6 +123,7 @@ test("language_detection_fuzzer") {
   ]
   deps = [
     ":libfuzzer_main",
+    "//base",
     "//components/translate/core/language_detection:language_detection",
   ]
 }