Fixes for re-enabling more MSVC level 4 warnings: courgette/ edition

This contains fixes for the following sorts of issues:
* Signedness mismatch

BUG=81439
TEST=none

Review URL: https://codereview.chromium.org/371153002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281696 0039d316-1c4b-4281-b951-d872f2087c98

courgette/disassembler_elf_32.h

@@ -30,7 +30,7 @@ class DisassemblerElf32 : public Disassembler {
   // class encapsulates this behavior.  public for use in unit tests.
   class TypedRVA {
    public:
-    explicit TypedRVA(RVA rva) : rva_(rva), offset_(-1) {
+    explicit TypedRVA(RVA rva) : rva_(rva), offset_(static_cast<size_t>(-1)) {
     }
 
     virtual ~TypedRVA() { };

courgette/disassembler_elf_32_arm.cc

@@ -215,7 +215,7 @@ uint16 DisassemblerElf32ARM::TypedRVAARM::op_size() const {
     case ARM_OFF21:
       return 4;
     default:
-      return -1;
+      return 0xFFFF;
   }
 }
 

courgette/encoded_program.cc

@@ -710,7 +710,7 @@ COMPILE_ASSERT(offsetof(RelocBlockPOD, relocs) == 8, reloc_block_header_size);
 class RelocBlock {
  public:
   RelocBlock() {
-    pod.page_rva = ~0;
+    pod.page_rva = 0xFFFFFFFF;
     pod.block_size = 8;
   }