diff --git a/layout/generic/nsLineLayout.cpp b/layout/generic/nsLineLayout.cpp
index ad75caf7d044..751905bc257f 100644
--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@@ -1040,7 +1040,7 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
   // the float.
   if (frameType) {
     if (nsLayoutAtoms::placeholderFrame == frameType) {
-      pfd->SetFlag(PFD_SKIPWHENTRIMMINGWHITESPACE, PR_TRUE);
+      pfd->SetFlag(PFD_ISPLACEHOLDERFRAME, PR_TRUE);
       nsIFrame* outOfFlowFrame = ((nsPlaceholderFrame*)aFrame)->GetOutOfFlowFrame();
       if (outOfFlowFrame) {
         // Make sure it's floated and not absolutely positioned
@@ -1103,9 +1103,6 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
     else if (nsLayoutAtoms::letterFrame==frameType) {
       pfd->SetFlag(PFD_ISLETTERFRAME, PR_TRUE);
     }
-    else if (nsLayoutAtoms::brFrame == frameType) {
-      pfd->SetFlag(PFD_SKIPWHENTRIMMINGWHITESPACE, PR_TRUE);
-    }
   }
 
   mSpaceManager->Translate(-tx, -ty);
@@ -2647,10 +2644,9 @@ nsLineLayout::TrimTrailingWhiteSpaceIn(PerSpanData* psd,
       }
     }
     else if (!pfd->GetFlag(PFD_ISTEXTFRAME) &&
-             !pfd->GetFlag(PFD_SKIPWHENTRIMMINGWHITESPACE)) {
-      // If we hit a frame on the end that we're not supposed to be skipping
-      // (not text, not a placeholder and not a br frame) then there is no
-      // trailing whitespace to trim. Stop the search.
+             !pfd->GetFlag(PFD_ISPLACEHOLDERFRAME)) {
+      // If we hit a frame on the end that's not text and not a placeholder,
+      // then there is no trailing whitespace to trim. Stop the search.
       *aDeltaWidth = 0;
       return PR_TRUE;
     }
diff --git a/layout/generic/nsLineLayout.h b/layout/generic/nsLineLayout.h
index a3677598887e..7e5e5c4aa431 100644
--- a/layout/generic/nsLineLayout.h
+++ b/layout/generic/nsLineLayout.h
@@ -353,15 +353,14 @@ protected:
 #define PFD_ISLETTERFRAME               0x00000010
 #define PFD_ISSTICKY                    0x00000020
 #define PFD_ISBULLET                    0x00000040
-#define PFD_SKIPWHENTRIMMINGWHITESPACE  0x00000080
-#define PFD_LASTFLAG                    PFD_SKIPWHENTRIMMINGWHITESPACE
+#define PFD_ISPLACEHOLDERFRAME          0x00000080
+#define PFD_LASTFLAG                    PFD_ISPLACEHOLDERFRAME
 
-    PRUint8 mFlags;
+    PRPackedBool mFlags;
 
     void SetFlag(PRUint32 aFlag, PRBool aValue)
     {
       NS_ASSERTION(aFlag<=PFD_LASTFLAG, "bad flag");
-      NS_ASSERTION(aFlag<=PR_UINT8_MAX, "bad flag");
       NS_ASSERTION(aValue==PR_FALSE || aValue==PR_TRUE, "bad value");
       if (aValue) { // set flag
         mFlags |= aFlag;
diff --git a/layout/html/base/src/nsLineLayout.cpp b/layout/html/base/src/nsLineLayout.cpp
index ad75caf7d044..751905bc257f 100644
--- a/layout/html/base/src/nsLineLayout.cpp
+++ b/layout/html/base/src/nsLineLayout.cpp
@@ -1040,7 +1040,7 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
   // the float.
   if (frameType) {
     if (nsLayoutAtoms::placeholderFrame == frameType) {
-      pfd->SetFlag(PFD_SKIPWHENTRIMMINGWHITESPACE, PR_TRUE);
+      pfd->SetFlag(PFD_ISPLACEHOLDERFRAME, PR_TRUE);
       nsIFrame* outOfFlowFrame = ((nsPlaceholderFrame*)aFrame)->GetOutOfFlowFrame();
       if (outOfFlowFrame) {
         // Make sure it's floated and not absolutely positioned
@@ -1103,9 +1103,6 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
     else if (nsLayoutAtoms::letterFrame==frameType) {
       pfd->SetFlag(PFD_ISLETTERFRAME, PR_TRUE);
     }
-    else if (nsLayoutAtoms::brFrame == frameType) {
-      pfd->SetFlag(PFD_SKIPWHENTRIMMINGWHITESPACE, PR_TRUE);
-    }
   }
 
   mSpaceManager->Translate(-tx, -ty);
@@ -2647,10 +2644,9 @@ nsLineLayout::TrimTrailingWhiteSpaceIn(PerSpanData* psd,
       }
     }
     else if (!pfd->GetFlag(PFD_ISTEXTFRAME) &&
-             !pfd->GetFlag(PFD_SKIPWHENTRIMMINGWHITESPACE)) {
-      // If we hit a frame on the end that we're not supposed to be skipping
-      // (not text, not a placeholder and not a br frame) then there is no
-      // trailing whitespace to trim. Stop the search.
+             !pfd->GetFlag(PFD_ISPLACEHOLDERFRAME)) {
+      // If we hit a frame on the end that's not text and not a placeholder,
+      // then there is no trailing whitespace to trim. Stop the search.
       *aDeltaWidth = 0;
       return PR_TRUE;
     }
diff --git a/layout/html/base/src/nsLineLayout.h b/layout/html/base/src/nsLineLayout.h
index a3677598887e..7e5e5c4aa431 100644
--- a/layout/html/base/src/nsLineLayout.h
+++ b/layout/html/base/src/nsLineLayout.h
@@ -353,15 +353,14 @@ protected:
 #define PFD_ISLETTERFRAME               0x00000010
 #define PFD_ISSTICKY                    0x00000020
 #define PFD_ISBULLET                    0x00000040
-#define PFD_SKIPWHENTRIMMINGWHITESPACE  0x00000080
-#define PFD_LASTFLAG                    PFD_SKIPWHENTRIMMINGWHITESPACE
+#define PFD_ISPLACEHOLDERFRAME          0x00000080
+#define PFD_LASTFLAG                    PFD_ISPLACEHOLDERFRAME
 
-    PRUint8 mFlags;
+    PRPackedBool mFlags;
 
     void SetFlag(PRUint32 aFlag, PRBool aValue)
     {
       NS_ASSERTION(aFlag<=PFD_LASTFLAG, "bad flag");
-      NS_ASSERTION(aFlag<=PR_UINT8_MAX, "bad flag");
       NS_ASSERTION(aValue==PR_FALSE || aValue==PR_TRUE, "bad value");
       if (aValue) { // set flag
         mFlags |= aFlag;