jni_generator: Avoid external linkage for registration methods.

This CL moves the generated registration methods to an anonymous
namespace so that targets can have multiple generate_jni_registration()
dependencies that use @NativeMethods.

Currently this would cause a link time error due to duplicate symbols
being defined.

Bug: 929661
Change-Id: I240b8848bd37adfc02de6d70f40f81c2a2f057aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1749481Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686389}

base/android/jni_generator/golden/testProxyNativesMainDex.golden

@@ -37,6 +37,8 @@ static const JNINativeMethod kMethods_org_chromium_base_natives_GEN_1JNIMAIN_DEX
 
 };
 
+namespace {
+
 JNI_REGISTRATION_EXPORT bool RegisterNative_org_chromium_base_natives_GEN_1JNIMAIN_DEX(JNIEnv* env) {
   const int number_of_methods = base::size(kMethods_org_chromium_base_natives_GEN_1JNIMAIN_DEX);
 
@@ -54,6 +56,8 @@ JNI_REGISTRATION_EXPORT bool RegisterNative_org_chromium_base_natives_GEN_1JNIMA
   return true;
 }
 
+}  // namespace
+
 
 // Step 4: Main dex and non-main dex registration functions.
 

base/android/jni_generator/golden/testProxyNativesMainDexAndNonMainDex.golden

@@ -44,6 +44,8 @@ static const JNINativeMethod kMethods_org_chromium_base_natives_GEN_1JNI[] = {
 
 };
 
+namespace {
+
 JNI_REGISTRATION_EXPORT bool RegisterNative_org_chromium_base_natives_GEN_1JNI(JNIEnv* env) {
   const int number_of_methods = base::size(kMethods_org_chromium_base_natives_GEN_1JNI);
 
@@ -61,6 +63,8 @@ JNI_REGISTRATION_EXPORT bool RegisterNative_org_chromium_base_natives_GEN_1JNI(J
   return true;
 }
 
+}  // namespace
+
 static const JNINativeMethod kMethods_org_chromium_base_natives_GEN_1JNIMAIN_DEX[] = {
     { "test_foo_Foo_thisismaindex", "()V",
         reinterpret_cast<void*>(Java_org_chromium_base_natives_GEN_1JNI_test_1foo_1Foo_1thisismaindex)
@@ -68,6 +72,8 @@ static const JNINativeMethod kMethods_org_chromium_base_natives_GEN_1JNIMAIN_DEX
 
 };
 
+namespace {
+
 JNI_REGISTRATION_EXPORT bool RegisterNative_org_chromium_base_natives_GEN_1JNIMAIN_DEX(JNIEnv* env) {
   const int number_of_methods = base::size(kMethods_org_chromium_base_natives_GEN_1JNIMAIN_DEX);
 
@@ -85,6 +91,8 @@ JNI_REGISTRATION_EXPORT bool RegisterNative_org_chromium_base_natives_GEN_1JNIMA
   return true;
 }
 
+}  // namespace
+
 
 // Step 4: Main dex and non-main dex registration functions.
 

base/android/jni_generator/golden/testProxyNativesRegistrations.golden

@@ -57,6 +57,8 @@ static const JNINativeMethod kMethods_org_chromium_base_natives_GEN_1JNI[] = {
 
 };
 
+namespace {
+
 JNI_REGISTRATION_EXPORT bool RegisterNative_org_chromium_base_natives_GEN_1JNI(JNIEnv* env) {
   const int number_of_methods = base::size(kMethods_org_chromium_base_natives_GEN_1JNI);
 
@@ -74,6 +76,8 @@ JNI_REGISTRATION_EXPORT bool RegisterNative_org_chromium_base_natives_GEN_1JNI(J
   return true;
 }
 
+}  // namespace
+
 
 // Step 4: Main dex and non-main dex registration functions.
 

base/android/jni_generator/jni_registration_generator.py

@@ -123,6 +123,8 @@ static const JNINativeMethod kMethods_${ESCAPED_PROXY_CLASS}[] = {
 ${KMETHODS}
 };
 
+namespace {
+
 JNI_REGISTRATION_EXPORT bool ${REGISTRATION_NAME}(JNIEnv* env) {
   const int number_of_methods = base::size(kMethods_${ESCAPED_PROXY_CLASS});
 
@@ -139,6 +141,8 @@ JNI_REGISTRATION_EXPORT bool ${REGISTRATION_NAME}(JNIEnv* env) {
 
   return true;
 }
+
+}  // namespace
 """)
 
   registration_call = string.Template("""\