Always mark synthesized interface bridges as pinned

Bug: 150443272, 150442580
Change-Id: I34b23745ac87267706c55ea0c6f4c74ea2b27590

src/main/java/com/android/tools/r8/R8.java

diff --git a/src/main/java/com/android/tools/r8/R8.java b/src/main/java/com/android/tools/r8/R8.java
index 2086f5e..c2a890e 100644
--- a/src/main/java/com/android/tools/r8/R8.java
+++ b/src/main/java/com/android/tools/r8/R8.java
@@ -336,6 +336,7 @@
         assert appView.rootSet().verifyKeptFieldsAreAccessedAndLive(appViewWithLiveness.appInfo());
         assert appView.rootSet().verifyKeptMethodsAreTargetedAndLive(appViewWithLiveness.appInfo());
         assert appView.rootSet().verifyKeptTypesAreLive(appViewWithLiveness.appInfo());
+        assert appView.rootSet().verifyKeptItemsAreKept(appView.appInfo().app(), appView.appInfo());
 
         appView.rootSet().checkAllRulesAreUsed(options);
 

src/main/java/com/android/tools/r8/shaking/Enqueuer.java

diff --git a/src/main/java/com/android/tools/r8/shaking/Enqueuer.java b/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
index 36afff6..582ee40 100644
--- a/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
+++ b/src/main/java/com/android/tools/r8/shaking/Enqueuer.java
@@ -2471,11 +2471,13 @@
     assert fieldAccessInfoCollection.verifyMappingIsOneToOne();
 
     for (ProgramMethod bridge : syntheticInterfaceMethodBridges.values()) {
-      appView.appInfo().invalidateTypeCacheFor(bridge.getHolder().type);
-      bridge.getHolder().appendVirtualMethod(bridge.getMethod());
-      targetedMethods.add(bridge.getMethod(), graphReporter.fakeReportShouldNotBeUsed());
-      liveMethods.add(
-          bridge.getHolder(), bridge.getMethod(), graphReporter.fakeReportShouldNotBeUsed());
+      DexProgramClass holder = bridge.getHolder();
+      DexEncodedMethod method = bridge.getMethod();
+      appView.appInfo().invalidateTypeCacheFor(holder.type);
+      holder.appendVirtualMethod(method);
+      targetedMethods.add(method, graphReporter.fakeReportShouldNotBeUsed());
+      liveMethods.add(holder, method, graphReporter.fakeReportShouldNotBeUsed());
+      pinnedItems.add(method.method);
     }
 
     // Ensure references from various root set collections.