More robust stack walks when the IP address in the context frame is invalid (or not in a known module).

This is achieved by:
1. Extending the span of the scan for return address in the conext frame.  Initially, I wanted to extend the span of the scan for all frames but then I noticed that there is code for ARM already that is extending the search only for the context frame.  This kind of makes sense so I decided to reuse the same idea everywhere.
2. Attempting to restore the EBP chain after a successful scan for return address so that the stackwalker can switch back to FRAME_TRUST_CFI for the rest of the frames when possible.

I also fixed the lint errors in the files touched.
Review URL: https://breakpad.appspot.com/605002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1193 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 1 insertions, 7 deletions

diff --git a/src/processor/stackwalker_arm.cc b/src/processor/stackwalker_arm.cc
index a736061b..b114fa17 100644
--- a/src/processor/stackwalker_arm.cc
+++ b/src/processor/stackwalker_arm.cc
@@ -166,14 +166,8 @@ StackFrameARM* StackwalkerARM::GetCallerByStackScan(
   uint32_t last_sp = last_frame->context.iregs[MD_CONTEXT_ARM_REG_SP];
   uint32_t caller_sp, caller_pc;
 
-  // When searching for the caller of the context frame,
-  // allow the scanner to look farther down the stack.
-  const int kRASearchWords = frames.size() == 1 ?
-    Stackwalker::kRASearchWords * 4 :
-    Stackwalker::kRASearchWords;
-
   if (!ScanForReturnAddress(last_sp, &caller_sp, &caller_pc,
-                            kRASearchWords)) {
+                            frames.size() == 1 /* is_context_frame */)) {
     // No plausible return address was found.
     return NULL;
   }