[heap] Remove obsolete constructors from SemiSpaceIterator.

src/heap/spaces.cc

Index: src/heap/spaces.cc
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index 9812abdf1e93cc6071938e84e198eff5513f7dfc..ee7751a5a89bf28abf6b0984ea12c554f5c000e7 100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -1846,21 +1846,12 @@ void SemiSpace::AssertValidRange(Address start, Address end) {
 
 // -----------------------------------------------------------------------------
 // SemiSpaceIterator implementation.
+
 SemiSpaceIterator::SemiSpaceIterator(NewSpace* space) {
   Initialize(space->bottom(), space->top());
 }
 
 
-SemiSpaceIterator::SemiSpaceIterator(NewSpace* space, Address start) {
-  Initialize(start, space->top());
-}
-
-
-SemiSpaceIterator::SemiSpaceIterator(Address from, Address to) {
-  Initialize(from, to);
-}
-
-
 void SemiSpaceIterator::Initialize(Address start, Address end) {
   SemiSpace::AssertValidRange(start, end);
   current_ = start;