Support getting the element cache size, clearing the element cache

WebDriverAgentLib/Commands/FBCustomCommands.m

@@ -38,6 +38,8 @@ + (NSArray *)routes
     [[FBRoute POST:@"/wda/homescreen"].withoutSession respondWithTarget:self action:@selector(handleHomescreenCommand:)],
     [[FBRoute POST:@"/wda/deactivateApp"] respondWithTarget:self action:@selector(handleDeactivateAppCommand:)],
     [[FBRoute POST:@"/wda/keyboard/dismiss"] respondWithTarget:self action:@selector(handleDismissKeyboardCommand:)],
+    [[FBRoute GET:@"/wda/elementCache/size"] respondWithTarget:self action:@selector(handleGetElementCacheSizeCommand:)],
+    [[FBRoute POST:@"/wda/elementCache/clear"] respondWithTarget:self action:@selector(handleClearElementCacheCommand:)],
   ];
 }
 
@@ -93,4 +95,16 @@ + (NSArray *)routes
   return FBResponseWithOK();
 }
 
++ (id<FBResponsePayload>)handleGetElementCacheSizeCommand:(FBRouteRequest *)request
+{
+  NSNumber *count = [NSNumber numberWithUnsignedInteger:[request.session.elementCache count]];
+  return FBResponseWithObject(count);
+}
+
++ (id<FBResponsePayload>)handleClearElementCacheCommand:(FBRouteRequest *)request
+{
+  FBElementCache *elementCache = request.session.elementCache;
+  [elementCache clear];
+  return FBResponseWithOK();
+}
 @end

WebDriverAgentLib/Routing/FBElementCache.h

@@ -31,6 +31,15 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (nullable XCUIElement *)elementForUUID:(NSString *__nullable)uuid;
 
+/**
+ Clears the cache
+ */
+- (void)clear;
+
+/**
+ Gets the number of elements in the cache
+ */
+@property (nonatomic, readonly) NSUInteger count;
 @end
 
 NS_ASSUME_NONNULL_END

WebDriverAgentLib/Routing/FBElementCache.m

@@ -47,4 +47,13 @@ - (XCUIElement *)elementForUUID:(NSString *)uuid
   return element;
 }
 
+- (void)clear
+{
+  [self.elementCache removeAllObjects];
+}
+
+- (NSUInteger)count
+{
+  return [self.elementCache count];
+}
 @end