De-ASTContext-ify DeclContext.

Remove ASTContext parameter from DeclContext's methods. This change cascaded down to other Decl's methods and changes to call sites started "escalating".
Timings using pre-tokenized "cocoa.h" showed only a ~1% increase in time run between and after this commit.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@74506 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/RewriteBlocks.cpp b/lib/Frontend/RewriteBlocks.cpp
index 29590de..bc855fa 100644
--- a/lib/Frontend/RewriteBlocks.cpp
+++ b/lib/Frontend/RewriteBlocks.cpp
@@ -306,39 +306,33 @@
 
 void RewriteBlocks::RewriteInterfaceDecl(ObjCInterfaceDecl *ClassDecl) {
   for (ObjCInterfaceDecl::instmeth_iterator 
-         I = ClassDecl->instmeth_begin(*Context), 
-         E = ClassDecl->instmeth_end(*Context); 
+         I = ClassDecl->instmeth_begin(), E = ClassDecl->instmeth_end(); 
        I != E; ++I)
     RewriteMethodDecl(*I);
   for (ObjCInterfaceDecl::classmeth_iterator 
-         I = ClassDecl->classmeth_begin(*Context), 
-         E = ClassDecl->classmeth_end(*Context);
+         I = ClassDecl->classmeth_begin(), E = ClassDecl->classmeth_end();
        I != E; ++I)
     RewriteMethodDecl(*I);
 }
 
 void RewriteBlocks::RewriteCategoryDecl(ObjCCategoryDecl *CatDecl) {
   for (ObjCCategoryDecl::instmeth_iterator 
-         I = CatDecl->instmeth_begin(*Context), 
-         E = CatDecl->instmeth_end(*Context); 
+         I = CatDecl->instmeth_begin(), E = CatDecl->instmeth_end(); 
        I != E; ++I)
     RewriteMethodDecl(*I);
   for (ObjCCategoryDecl::classmeth_iterator 
-         I = CatDecl->classmeth_begin(*Context), 
-         E = CatDecl->classmeth_end(*Context);
+         I = CatDecl->classmeth_begin(), E = CatDecl->classmeth_end();
        I != E; ++I)
     RewriteMethodDecl(*I);
 }
 
 void RewriteBlocks::RewriteProtocolDecl(ObjCProtocolDecl *PDecl) {
   for (ObjCProtocolDecl::instmeth_iterator 
-         I = PDecl->instmeth_begin(*Context), 
-         E = PDecl->instmeth_end(*Context); 
+         I = PDecl->instmeth_begin(), E = PDecl->instmeth_end(); 
        I != E; ++I)
     RewriteMethodDecl(*I);
   for (ObjCProtocolDecl::classmeth_iterator 
-         I = PDecl->classmeth_begin(*Context), 
-         E = PDecl->classmeth_end(*Context); 
+         I = PDecl->classmeth_begin(), E = PDecl->classmeth_end(); 
        I != E; ++I)
     RewriteMethodDecl(*I);
 }
@@ -1147,8 +1141,8 @@
   }
   if (RecordDecl *RD = dyn_cast<RecordDecl>(D)) {
     if (RD->isDefinition()) {
-      for (RecordDecl::field_iterator i = RD->field_begin(*Context), 
-             e = RD->field_end(*Context); i != e; ++i) {
+      for (RecordDecl::field_iterator i = RD->field_begin(), 
+             e = RD->field_end(); i != e; ++i) {
         FieldDecl *FD = *i;
         if (isBlockPointerType(FD->getType()))
           RewriteBlockPointerDecl(FD);