Prune forward declarations in isolate.h

Change-Id: Id31c1178b84be5ec4e876495ce220302864713e0
Reviewed-on: https://chromium-review.googlesource.com/1240118Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56166}

src/code-stubs.h

@@ -12,6 +12,7 @@ namespace v8 {
 namespace internal {
 
 // Forward declarations.
+class CodeStubDescriptor;
 class Isolate;
 namespace compiler {
 class CodeAssemblerState;

src/isolate.h

@@ -59,42 +59,32 @@ namespace heap {
 class HeapTester;
 }  // namespace heap
 
-class AccessCompilerData;
 class AddressToIndexHashMap;
 class AstStringConstants;
 class Bootstrapper;
 class BuiltinsConstantsTableBuilder;
 class CancelableTaskManager;
 class CodeEventDispatcher;
-class ExternalCodeEventListener;
-class CodeGenerator;
-class CodeRange;
-class CodeStubDescriptor;
 class CodeTracer;
 class CompilationCache;
 class CompilationStatistics;
 class CompilerDispatcher;
 class ContextSlotCache;
 class Counters;
-class CpuFeatures;
 class Debug;
 class DeoptimizerData;
 class DescriptorLookupCache;
-class EmptyStatement;
 class EternalHandles;
 class ExternalCallbackScope;
 class HandleScopeImplementer;
 class HeapObjectToIndexHashMap;
 class HeapProfiler;
-class InlineRuntimeFunctionsTable;
 class InnerPointerToCodeCache;
-class InstructionStream;
 class Logger;
 class MaterializedObjectStore;
 class Microtask;
 class OptimizingCompileDispatcher;
 class PromiseOnStack;
-class Redirection;
 class RegExpStack;
 class RootVisitor;
 class RuntimeProfiler;
@@ -103,10 +93,7 @@ class SetupIsolateDelegate;
 class Simulator;
 class StartupDeserializer;
 class StandardFrame;
-class StatsTable;
-class StringTracker;
 class StubCache;
-class SweeperThread;
 class ThreadManager;
 class ThreadState;
 class ThreadVisitor;  // Defined in v8threads.h