Remove some asserts to speed up debug mode.

src/spaces.h

Index: src/spaces.h
===================================================================
--- src/spaces.h	(revision 9581)
+++ src/spaces.h	(working copy)
@@ -642,7 +642,6 @@
   // [page_addr + kObjectStartOffset .. page_addr + kPageSize].
   INLINE(static Page* FromAllocationTop(Address top)) {
     Page* p = FromAddress(top - kPointerSize);
-    ASSERT_PAGE_OFFSET(p->Offset(top));
     return p;
   }
 
@@ -666,7 +665,6 @@
   // Returns the offset of a given address to this page.
   INLINE(int Offset(Address a)) {
     int offset = static_cast<int>(a - address());
-    ASSERT_PAGE_OFFSET(offset);
     return offset;
   }
 
@@ -1741,7 +1739,6 @@
         reinterpret_cast<Address>(reinterpret_cast<uintptr_t>(address_in_page) &
                                   ~Page::kPageAlignmentMask);
     NewSpacePage* page = reinterpret_cast<NewSpacePage*>(page_start);
-    ASSERT(page->InNewSpace());
     return page;
   }
 
@@ -1818,7 +1815,6 @@
 
   // Returns the start address of the current page of the space.
   Address page_low() {
-    ASSERT(anchor_.next_page() != &anchor_);
     return current_page_->body();
   }
 
@@ -2084,7 +2080,7 @@
 
   // Return the current capacity of a semispace.
   intptr_t EffectiveCapacity() {
-    ASSERT(to_space_.Capacity() == from_space_.Capacity());
+    SLOW_ASSERT(to_space_.Capacity() == from_space_.Capacity());
     return (to_space_.Capacity() / Page::kPageSize) * Page::kObjectAreaSize;
   }
 
@@ -2317,9 +2313,9 @@
 // For contiguous spaces, top should be in the space (or at the end) and limit
 // should be the end of the space.
 #define ASSERT_SEMISPACE_ALLOCATION_INFO(info, space) \
-  ASSERT((space).page_low() <= (info).top             \
-         && (info).top <= (space).page_high()         \
-         && (info).limit <= (space).page_high())
+  SLOW_ASSERT((space).page_low() <= (info).top             \
+              && (info).top <= (space).page_high()         \
+              && (info).limit <= (space).page_high())
 
 
 // -----------------------------------------------------------------------------